Science method

# X-ray Diffraction - Science method

The scattering of x-rays by matter, especially crystals, with accompanying variation in intensity due to interference effects. Analysis of the crystal structure of materials is performed by passing x-rays through them and registering the diffraction image of the rays (CRYSTALLOGRAPHY, X-RAY). (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
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The ratio
For a good quantitative phase analysis you need to run a Rietveld refinement of your diffraction pattern.
Provide full information: What is the wave length, the diffractometer type, sample preparation etc etc. Without wave length, a 2Theta scale is completely meaningless. What is the "amorphous" background in the 2Theta range 20 to 45 due to, what is the strange background below 15 degrees??
Are you sure your phase assignments are correct?
With Cu2O in Pn-3m and CuO in C2/c, CuO does not have a strong reflection at roughly 44°2Theta@CuKalpha, see calculated diffraction pattern
Cu2O Pn-3m a= 4.252 Ang
CuO C2/c ; a=4.65300 b=3.41000 c= 5.10800 , beta = 80.52
What is FTO ?
Your "Pure Cu2O" does not seem to be Cu2O only ????
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I performed XRD analysis of my chitosan sample, I would like to ask for help to interpret its diffractogram. If its possible could someone share with me chitosan
JCPDS card 039-1894?
Thank you,
Kindly
Flynne
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What analysis, SEM or TEM, is better for MOF identification? Unfortunately, I only have one choice.
I have the crystal size average with XRD, and therefore, I think SEM is better.
In your question you say SEM or TEM for MOF identification. Do you want to identify what? Grain sizes? Crystallite sizes? The crystal phase? In this last case you need to use electronic diffraction of TEM (from SAED) or HR-TEM...
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What is the incident radiation used in XPS and why? How does the detector used in the XPS differ from those during SEM, EDX or XRD data collection?
In XРS ( X-ray photoelectron spectroscopy) measures the binding energy of electrons with a nucleus when irradiated with monochromatic radiation, which appear as a result of the photoelectric effect.
Scanning electron microscope (SEM). The incident electrons interact with the atoms in the sample, creating various signals that contain information about the surface topography and composition of the sample. The electron beam is scanned as a bitmap and the position of the beam is combined with the intensity of the detected signal to produce an image.
Energy dispersive X-ray spectroscopy(EDX). The electron beam is focused on the sample and transfers electrons from one shell to another. This releases X-rays. The amount and energy of the x-rays emitted by the sample can be measured using an energy dispersive spectrometer. Since the energies of X-rays characterize the difference in energy between the two shells and the atomic structure of the emitting element, EDS makes it possible to measure the elemental composition of the sample.
XRD identification of materials based on their diffraction pattern. The sample is irradiated with X-rays and the intensity of the rays leaving the sample is measured depending on the angles of the crystal lattice.
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i could not find out JCPDF card for XRD results of this compound in xpert high score. how can I interprete this?
The answer to your question is in your question: the compound is new, so if it was not studied before you do not find crystallographic information. However, you can try to find similar compounds, having similar stoichiometry and maybe some structural similarity..or as suggested by R. B. Neder search the phases containing the elements of your compound, maybe something fit...
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Is this comparison can give more information regarding the preferred orientation of low-dimensional perovskite film? Layered 2D Perovskite thin film shows repetitive PXRD peak partner.
Because of the paculiar architecture of 2DLP and their preferencial orientation parallel to the substrate, provide intense basal reflection from the 00l plane, of the inorganic layer. However, if you break the orientation by grinding the powder you may also get the other reflections, masked otherwise. However,
In the case of thinfilm your material is constrained to the substrate and you end up with the intense basal reflections.
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How we can calculate the value of the Elastic constants From XRD data for a new compounds for which no theoritical values of the same was provided in literature
and after calculating such values how can we say these are accurate or appropriate or just an estimation?
To get some feedback, please refer to the latest preprint article at link DOI: 10.13140/RG.2.2.27720.65287/3.or at link https://www.researchgate.net/publication/352830671
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Reputable all,
It's humble request for facts approximately correlation between variation of conductivity of material with XRD Pattern.From some other studies the conductivity of polymeric material is increasing with sensitisation.Can it's feasible to explain through the xrd peaks broadening pattern?
To get a sustainable solution to your problem, please refer to the preprint article given at link DOI: 10.13140/RG.2.2.27720.65287/3 or at link https://www.researchgate.net/publication/352830671.
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how much sample size is needed for SEM & XRD analysis of Carbon fiber brush electrode, in MFC, only bristles can be used for these analyses, or the titanium wire can also be used?
SEM and XRD are the best techniques for morphological and structural characterization, requiring a sample size of around a pea-size powder volume.
Thanks
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Attached file show's the unreal peaks in deferent positions for same sample SI SUBSTR with 0 background measured many times.
to my opinion these 'peaks' are not due to x-ray diffraction; they are too narrow for real diffraction lines.
It seems to me, that you have got a malfuction of your detector system, e.g some EM-interference with surrounding electric/electronic equipment.
a) Sparking the defect starters of neon tube may induce such spikes in your XRD pattern... Please have a look for example in or around your lab for a 'blinking' neon tube...
b) You should also check (install) the electrical grounding of your experimental set up; especially that of the x-ray tube. You may operate your system at lower tube voltages and see what is happening now (sparking may arise from the HV of the tube)
Best regards
G.M.
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Hello RG members,
I have recently deposited copper thin film using magnetron sputtering system. I have characterized those samples using XRD. From the XRD results, I have obtained a peak of single plane of Cu along with peaks of multiple planes of Cu2O. If I want to measure the degree of crystallinity of Cu How can I do it? Any suggestions
To get sustainable solution of your issue/question, I sincerely recommend the preprint article available at link DOI: 10.13140/RG.2.2.27720.65287/3. For an alternative link https://www.researchgate.net/publication/352830671.
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I need a method to determine the material from the XRD graph and what are the key points that I should always keep in mind while interpreting an XRD graph?
You need a crystallographic database to compare your experimental peak positions with those of well known crystal structures. Your pattern seems constituted by different phases: a more crystalline one with the narrower peaks, it seems a structure very symmetric of a metal or oxide and the peak at 25° broader of a nanocrystalline component. From an XRD pattern many information can be derived, it depends on your aims
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The phi scan of XRD is tilting the holder to diffaract another crystal plane. If the crystal is single crystal or bought from a company, I think the quality should be very good. But why the peaks of phi scan are not the same intensity, even have big difference?
To get sustainable solution of your issue/question, I sincerely recommend the preprint article available at link DOI: 10.13140/RG.2.2.27720.65287/3. For an alternative link https://www.researchgate.net/publication/352830671.
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Hi,
I have tried taking XRD of CoS2 nanostructures grown on carbon cloth. Since carbon cloth has a bumpy surface as well as the thickness of the sample is very less compared to the carbon cloth substrate, I am unable to obtain XRD of the sample (Including Gracing incidence XRD) (see figure, showing XRD patterns of CoS2 grown on carbon cloth (CoS2/CC) and bare CC). Some papers suggest to sonicate the sample and etch out the nanostructures from CC for XRD. But I am getting very small quantity in that way. Kindly suggest any alternative ways if posssible.
Thank you.
Have you tried to substract the pattern of bare CC from the other one? Some small peaks appear in that containing CoS2. Which kind of information on CoS2 you want to determine? Do you want only evidence its presence, or determine its lattice parameters or other?
However, the XRD pattern can be also obtained on small amount of sample
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This is an XRD pattern of limestone powder constating of Quartz, Calcite, Dolomite mainly.
Is there chance you can help checking and finding the phase quantification of the below XRD pattern?
An approximate numbers will surely help me to interpret some of my work. I have noted the first intense peaks for those 3 major phases of the minerals in the limestone.
Calcite is more than 40 % and Quartz is below 10%. Any approximate numbers based on intensity ratio is great.
Hello,
quantification that is based only on the ratio of intensities is extremely imprecise and often leads to completely wrong results. The reason is, among other things, significant differences in the absorption coefficients for calcite and quartz, as well as possible texturing. Nowadays, it is not a problem to determine the approximate proportions of phases using programs for the Rietveld method of diffraction data processing. Some of these programs are also free to download, for example Profex.
In addition to the mentioned minerals, in the attached diffraction pattern I also see small proportions of feldspars and clay minerals.
If you publish the measurement file (raw, dat. xy etc.) I can try to quantify it.
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Hello
I wanted a thesis topic in the field of food grade nanostructured lipid carrier (NLC) to work with NMR, XRD and DSC. Can you make suggestions?
You can address the Effect of Solid Lipid Nanoparticle Incorporation on the Lipid Digestion Kinetics and Bioaccessibility of Encapsulated Bioactive Compounds in Food Grade Nanostructured Lipid Carriers: A NMR, XRD, and DSC Study.
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I do not understand well your question. A doped material has a different composition with respect to the original one, a nanomaterial has low sizes, reflecting in the peak broadening of the pattern. The doping could produce variation in peak positions and/or peaks integrated intensities. Which is your right request?
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I found this XRD peak list but exactly don't know what compound peak list it is.
For this, please check the latest preprint article at DOI: 10.13140/RG.2.2.27720.65287
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During my time processing results curves, I frequently need to correct the baseline before peak fit, and intensity comparison. This thing happens to XRD, XPS, Raman, and many other data processing. Can anyone give some advice on the general principle of baseline correction and some specific rules for each type of measurement? For example, I heard that the (FWHM) can not be higher than a specific eV value when processing XPS data.
Hope that helps.
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its showing lower intensities and shift towards higher angles.
CBN was subject of my investigations in different morphological forms. Please, open my site here in RG. You can find a lot of interesting information about this beautiful material.
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Bragg's equation
For this, please check the article, DOI: 10.13140/RG.2.2.27720.65287
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I am using X'Pert HighScore Plus. I want to do the deconvolution/unfolding of the pure XRD profile pattern of my sample from the diffraction pattern of the sample and the XRD pattern of a Si standard. Both patterns are obtained from the same instrument. i.e., I want a third XRD pattern which is free from the instrumental broadening.
How can I do this using X'Pert HighScore Plus?
Although I prefer this software, I'm also open to learn other program. I really appreciate any help.
Thank you
For this, please check the article, DOI: 10.13140/RG.2.2.27720.65287
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I'm looking for software to view .xrdml files. I need to be able to do basic manipulations (scale patterns and shift the 2-theta axis) and overlay arbritary numbers of patterns. Making peak tables would be nice too.
I don't need to do Rietveld refinements or other fittings.
What packages are people using for basic XRD pattern viewing?
Frank
For this, please check the article, DOI: 10.13140/RG.2.2.27720.65287
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I have made xrd data from angle 2 to 6o degree. what does mean here of important scan angles?
@Gerhard Martens you're right! I forgot to mention the slight difference in the reciprocal lattice vectors definition assumed by the crystallography and solid state physic communties.
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I already synthesize metal oxide compounds and I characterized by XRD and SEM. I found new morphology but I don't know how to draw crystal structure. I have XRD to confirm my compound is CoO and Co3O4 and in SEM I found new crystal shape from my methods. I plan to measure TEM to get diffraction pattern and plane of diffraction. After that I need to draw crystal structure from my new crystal shape to present my new shape of oxide compound. How can I draw or simulation mr crystal structure from TEM or I have to do another characterization techniques?
Please check the fully-ready preprint article DOI: 10.13140/RG.2.2.27720.65287/3, Title: Qualitative Analyses of Thin Film-Based Materials Validating New Structures of Atoms
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In gC3N4 (graphitic carbon nitride), XRD results reveal the formation peaks corresponding to the 002 planes, which reveal a crystalline phase. But when we examine the interference pattern and SAED pattern images from HRTEM we can't find the lattice interference for gC3N4, which appears to be amorphous.
what could be the reason for this? how can the HRTEM be interrelated to XRD peak formation?
Please check the fully-ready preprint article DOI: 10.13140/RG.2.2.27720.65287/3, Title: Qualitative Analyses of Thin Film-Based Materials Validating New Structures of Atoms
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Many studies have explained the changes in peak intensity in XRD patterns of irradiated polymeric films, but I have found little information on the shift effect. Could someone please provide some assistance?
Dear friend Tasnime Rasselkaf
Gamma irradiation can cause structural changes in polymeric materials due to the energy of the ionizing radiation interacting with the material. One of the effects of this interaction can be a shift in the XRD peaks compared to the virgin sample. This shift can be attributed to changes in the crystalline structure of the material, which can affect the spacing between the planes of atoms that produce the diffraction peaks.
Several mechanisms can cause peak shifts in XRD patterns of irradiated polymeric films, including the introduction of free radicals, crosslinking, and chain scission. These mechanisms can result in changes in the degree of crystallinity, crystallite size, and orientation of the polymer chains, which can affect the XRD pattern.
In some cases, the peak shift can be used to estimate the degree of crosslinking or chain scission in the polymeric material. However, interpreting peak shifts in XRD patterns of irradiated polymeric films can be challenging and may require additional analysis techniques to confirm the structural changes in the material.
References:
1. K. Bouchoucha, F. Guinneton, and M. Fontaine, "X-ray diffraction analysis of polyethylene irradiated in air or in vacuum," Journal of Applied Polymer Science, vol. 85, pp. 2115-2122, 2002.
2. J. F. Scott and T. T. Xu, "X-ray diffraction studies of gamma irradiated and thermally annealed polyethylene," Journal of Polymer Science Part B: Polymer Physics, vol. 33, pp. 1841-1849, 1995.
3. M. Arunachalam, V. K. Gupta, and P. K. Sehgal, "XRD and SEM studies of gamma irradiated LDPE," Radiation Physics and Chemistry, vol. 74, pp. 249-252, 2005.
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I had an Mg(OH)2 (nano) sample where I had an XRD pattern which looks just fine.
The same sample was taken to undergo a TEM analysis along with SAED. The SAED pattern were missing the (101) line despite being the major line in the XRD pattern.
to my opinion, here you have a nice example of a preferred orientation artifact.
In contast the XRD, which will give you a diffraction pattern averaged over the full sample surface and thus collecting the data from a very lot of crystallites, here in the SAED mode, you have only a few crystallites in the field of view. These few crystallites cannot cover the whole 4pi directional space 'dense' enough to give you all the diffraction peaks. Thus the 101 one may missing here. You should average your SEAD pattern over a lot of sample points.
However, even when doing that average, your may still miss that peak, due to an overall preferred orientation of the crystallites in your very thin sample...
Best regards
G.M.
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The mass faction and volume fraction is same thing. I calculate the the Percent volume fraction by XRD data with the help of formula.
(CuTl-1223) % = × 100
(CuTl-1234) % = × 100
(CuTl-1212) % = × 100 ……….. (1)
(Unknown impurity) % = × 100
Rietveld analysis is a powerful method for determining the crystal structure and phase composition of materials from X-ray diffraction (XRD) data. However, it cannot directly provide the mass fractions of individual phases.
To estimate the mass fractions, additional information is needed, such as the densities of the individual phases and the total mass of the sample. The mass fraction of a phase is equal to the volume fraction of the phase multiplied by its density. The volume fraction of a phase can be calculated from the Rietveld analysis by dividing the integrated intensity of the diffraction peaks from that phase by the total integrated intensity of all phases in the sample.
Once the volume fractions of the individual phases are determined, the mass fractions can be estimated using the following formula:
Mass fraction = Volume fraction x Density
The densities of the individual phases can be obtained from the literature or by experimental measurements such as Archimedes' principle or pycnometry.
It is important to note that the estimated mass fractions obtained from XRD data may not be very accurate due to various factors such as preferred orientation, peak overlap, and other instrumental and experimental factors.
References:
1. Cullity, B. D., & Stock, S. R. (2001). Elements of X-ray diffraction (3rd ed.). Prentice-Hall.
2. Young, R. A. (1995). The Rietveld method. Oxford University Press.
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HELLO,
i would like to ask a help for finding proper peak for my XRD results.
What i believe is my product shows crytallinity of WO2.90, but i am pretty not sure that this really is.. i put the JCPDS card of WO2.90 Below my XRD results, am i right?
or else, is there somebody who can help to fit the peak of it?
I have now gone through the ICSD database (unequal ICDD). The narrow reflections (which you already have identified as higher orders (010) and (020) based on some ICDD/PDF entry) most likely correspond to the W-W distance resulting from W-O-W bridge due to corner-sharing octahedra (d approximately 3.8 Å; assuming that your data were collected with Cu radiation). A significant number of WO3-x structures are variants of the ReO3 structure having a pseudocubic lattice parameter of this 3.8 A. According to a couple of structures of WO3-x I have looked at now, one of these directions is retained as translation vector and usually ends up as shortest lattice parameter in the structure descriptions. It can in principle end up as a, b or c, depending on the choice of axes. Perpendicular you then have more complicated connectivities, including edge sharing of octahedra and pentagonal bipyramids around W. However, the 3.8 A remains as some lattice parameter! The more complicated structure motifs occurring perpendicular to the 3.8 A direction are then more prone to growth errors. Hence you have the narrow e.g. (001) and (002) or (010) and (020) and the rest gets strongly broadened. This is your broad reflections! Your task is now to go through the different structures available in the literature, simulate the diffraction patterns and look at what is additional to what is in your case the narrow reflections. Perhaps you find also some kind of review of the structure systematics of WO3-x.
Note that there are likely different series of structures which can be relevant and they occur sometimes under somewhat arbitrary names/formulas. There is the concept of chemical shear/twinning (Hyde&Andersson?) by which you in principle can generated infinitely many structures of arbitrary composition. In that case apparently quite different crystal structures can yield quite similar diffraction patterns. Superspace can then be used to work out the similarity and to work out the evolution of the diffraction patterns. Since I mention the ICSD (unequal ICDD) database: Not all interesting structures are there. Again, databases are mainly for inspiration, and they are full of error (although sometimes the also expose errors in the original literature)!
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What is Ca5.40Mg0.60C6.00O18.00 (detected in XRD)? Is it same as dolomite?
Ca5.40Mg0,6C6O18 = Ca0.9Mg0.1 CO3 = calcite with increased Mg content. The boundary value between magnesian calcite and calcite is not clearly defined. Sometimes 0.1 or even 0.25.
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Hi everyon, im a student, i have a inorganic chemistry experiment class and i need to analysis XRD of Al2O3 before and after heating to 1000oC, i dont know why is the pattern of this compound changed? Maybe they lost initial impurities? As i known, Al2O3 has a temperature melting 2072oC. Someone can help me to solve this problem. Thank you.
X-ray diffraction (XRD) is a powerful analytical technique used to study the crystal structure of materials. When a material is subjected to high temperature, it can undergo various changes in its crystal structure, which can be reflected in its XRD pattern.
Al2O3, also known as aluminum oxide, is a commonly used material in many industries due to its high melting point, excellent thermal stability, and good electrical insulating properties. When Al2O3 is heated to 1000°C, it undergoes a phase transformation from alpha-Al2O3 to gamma-Al2O3.
The crystal structure of alpha-Al2O3 is rhombohedral, while gamma-Al2O3 has a cubic crystal structure. This change in crystal structure results in a change in the XRD pattern of the material.
Before heating, the XRD pattern of Al2O3 typically shows sharp peaks corresponding to the rhombohedral crystal structure of alpha-Al2O3. After heating to 1000°C, the XRD pattern shows broader peaks corresponding to the cubic crystal structure of gamma-Al2O3.
Therefore, the XRD pattern of Al2O3 changes before and after heating to 1000°C due to the phase transformation from alpha-Al2O3 to gamma-Al2O3.
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I tried some of them but hard to get one that is free to download and work on MacBook.
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I'm trying to understand how theoretical powder XRD patterns are calculated in VESTA. I figured one way to learn that without the computer programming based nuances is to just do it in Excel.
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Does the coating thickness affect the XRD peak intensity?
there are two aspects of your question;
a) XRD taken from the coating ( e.g. a (thin) film) on top of a substrate:
XRD peak intensity (height) increases with coating thickness up to about two 2 to three times the penetration depth of the x-rays in the coating material (theta dependent).
b) XRD taken from material behind the coating of thickness d:
x-ray attenuation of the coating will cause a reduction of the XRD peak height(s) from the material; with increasing coating thickness d the peaks will go down until they vanish in the noise. This will be achieved for d being equal to about two to three times of the penetration depth of the x-rays in the coating (also theta dependent).
For the meaning of x-ray attenuation and penetration depth you may have a look at the presentations listed in the publication section of my RG home page ...
Best regards
G.M.
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I prepared thin PDMS film embedded with CsPbBr3 Perovskite quantum dot and doped Ag+ ions to PQDs inside PDMS. The XRD results showed that the peak intensity of (100) plane increased while intensity of all other peaks seriously decreased after Ag+ ion doping. What are the possible reasons for this changes in XRD pattern?
Given the large peak width (100), I would think that doping with silver reduces the degree of crystallinity of the material.
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I recently found a free program for XRD data analasys called QualX, that was made on Bari Institute of crystalography and I want to know if anyone has any experience with it.
Dear friend Matic Meglič
QualX is a well-known and widely used software for phase identification and quantitative analysis of XRD data. It is developed by the Institute of Crystallography - CNR in Italy and is available for free download. The software has a user-friendly interface and supports several data formats. It also allows users to customize various parameters and settings for data analysis.
It can be used for phase identification, peak profile analysis, and quantification of crystalline materials.
Here are the basic steps to use QualX for phase identification:
1. Open the software and create a new project.
2. Import your XRD data file in one of the supported formats (e.g. .txt, .xy, .ras).
3. Calibrate the XRD instrument by setting the parameters such as radiation type, wavelength, and detector distance.
4. Choose the peak search method and set the search parameters such as angle range, step size, and peak intensity threshold.
5. Identify the phases present in the sample by comparing the peak positions and intensities with those of known reference materials in the database. You can either use the software's built-in database or create your own custom database.
6. Refine the results by adjusting the peak positions and intensities, if necessary.
7. Generate a report that summarizes the identified phases, their relative abundance, and other relevant information.
It is important to note that the accuracy of the phase identification results depends on the quality of the XRD data, the peak search method used, and the completeness of the reference database. Therefore, it is recommended to use high-quality XRD data and to update the reference database regularly.
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crystallite size is usually determined by X- ray diffraction. Can it be cross verified by transmission ebsd (t-ebsd)?
Yes, crystallite size can also be determined by Transmission Electron Backscatter Diffraction (t-EBSD) in addition to X-ray diffraction (XRD). In t-EBSD, the crystalline structure of the material is studied using an electron beam instead of X-rays used in XRD. By measuring the intensity and width of the diffraction patterns obtained from the electron beam interacting with the sample, the size and orientation of the crystallites in the sample can be determined.
However, it should be noted that the crystallite size measured by t-EBSD may not necessarily match with the crystallite size measured by XRD, as the two techniques are based on different principles and have different resolution limits. Additionally, the choice of the technique to use for determining the crystallite size depends on several factors such as the type of material being studied, the required accuracy, and the available equipment.
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??
The degree to which XRD can be used to clearly differentiate between different types of rocks and soil depends on a variety of factors, such as the complexity of the sample matrix and the mineralogical diversity of the sample. In most cases, XRD alone may not be sufficient to fully characterize a given sample, and other complementary techniques may be needed in order to gain a more complete picture of the sample's composition and structure.
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How to determine the crystal structure from XRD Pattern. I do not have the XRD data
Basically, in addition to single crystal xrd pattern, pxrd pattern could be used to determine crystal structure of some more or simple compounds.
After phase identification and rietveld refinement using MATCH software,
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Cellulose powder was used as a precursor and following synthesis route was followed. Drying at 180C for 12 hours. Carbonization at 1300C (vacuumed and filled with argon) for a hold time of 1 hour. 0-800 at 8C/min, 800-1000 @ 5C/min, 1000-1300 @ 8C/min. Same cycle was used for cooling.
I'm attaching the XRD and picture after attaching.
Perhaps you ended up with galssy carbon with impurities? If you thint you are handling with pure carbon, compare with XRD of graphite or glassy carbon and also diamond. I can see quite a good deal of amorphous barckground, and the first peak almost coinciding with broad hump might mean avg. short range distance btween atoms is equal to some significant lattice parameter, giving credence to diamond cubic or hexagonal carbon structure.
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I made Hap using sol-gel method by dissolving mussel shell powderin acetic acid and using this calcium solution to make hydroxyapatite via dropwise addition of phosphoric acid till pH=10, oven dry it and calcinated it.
After synthesizing HA, I conducted an XRD analysis of this sample, I found peaks pertaining to standard hydroxyapatite but I also found traces of CaO peaks.
Could you suggest how this happened?
-Thank you
Thank you, Sir. I will look into it.
I appreciate your positive responses to my question.
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Can you suggest some good book /literature for understanding the Rietveld refinement method.
Modern Powder Diffraction ; B. Toby
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Following the Modified Hummers method we have tried to prepare GO from natural graphite flakes. But we found two Bragg peaks ~11 and ~26 in XRD. It seems some graphite has not undergone to oxidize (according to the previous report). We used 1:0.5 (case-1) and 1:1 (case-2) graphite and NaNO3 for the synthesis.
The XRD patterns of as-synthesized samples are included below, please find them.
Dear Dr. Gerhard Martens,
Thank you for sharing your valuable comment.
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I need an online course about characterization techniques of materials such as XRD, XRF, XPS, Raman Spectra, XANES, SEM, TEM
As you read, you can get it on OpenCourseWare platform. only go to Google search and then write the name of the platform.
or you can open https://ocw.mit.edu/ .
Best regards
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I have XRD data for my MOF but finidng it difficult to analyse the data in XpertHighscore plus software
Thank you Sir Kaushik Shandilya. Really helpful outline sir.
Would like to ask more about Indexing peaks. The match that I am finding is not exact. It has lot more peaks than my structure. What should be done in such a situation. Please advise sir.
Thanks & Regards,
Prerana Loomba
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What does it mean when quantitative analysis of the compositional elements (from EDS analysis) gives the weight percentage and Atomic percentage of the elements with a negative sign, for example( -1.05) while the existence of this element from XRD analysis and the elemental mapping images?
Negative sign means absence of element (usually because of poor understanding of the method by operator). And "XRD analysis and the elemental mapping" usually cannot prove presence of an element. Use spectra to make a qualitative analysis before conducting a quantitative one.
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I have XRD data for a metal-organic framework (MOF), and I tried to use the X'pert Highscore Plus software to identify the standard data (JCPDS), but I was unable to identify the high-score candidate for it. Your assistance would be much appreciated if you could help me solve it.
Kaushik Shandilya Many thanks for your response. When I search for match data, do I have to select all elements in my MOFs? please
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XRD peak position and width same but intensity is different means?
If the X-ray diffraction (XRD) peak position and width are the same, but the intensity of the peak is different, it could indicate a difference in the amount of crystallinity of the material being analyzed.
The intensity of an XRD peak is related to the number of atoms in the crystal that are capable of scattering X-rays. Therefore, a higher peak intensity indicates a higher number of atoms in the crystal, which could indicate a higher degree of crystallinity or larger crystal size. On the other hand, a lower peak intensity could suggest a lower degree of crystallinity or smaller crystal size.
However, it's important to note that there could be other factors that affect peak intensity, such as sample preparation, instrument settings, and data analysis techniques. Therefore, it's necessary to consider all factors and perform additional analyses to accurately interpret XRD data.
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What is the physics mechanism behind that??
X-ray diffraction (XRD) is a technique used to determine the crystal structure of a material by analyzing the diffraction pattern produced when X-rays are scattered by the material's atomic lattice. The diffraction pattern consists of a series of peaks that correspond to different planes of atoms in the crystal lattice.
When there are variations in the crystal structure or lattice parameters, the position of the XRD peaks can shift to either higher angles or lower angles. This shift in the position of the peak is known as a shift in the "2θ" angle, which is the angle between the incident X-ray beam and the detector.
If the XRD peak shifts towards lower angles, it means that the lattice parameter of the crystal has increased or the crystal structure has expanded. This expansion can be due to factors such as the incorporation of impurities or defects into the crystal structure, or changes in the temperature or pressure of the sample. In other words, a shift towards the lower angle side indicates an increase in the unit cell dimensions.
On the other hand, if the XRD peak shifts towards higher angles, it means that the lattice parameter of the crystal has decreased or the crystal structure has contracted. This contraction can be due to factors such as the removal of atoms from the crystal lattice or the application of external pressure or strain. In other words, a shift towards the higher angle side indicates a decrease in the unit cell dimensions.
It is important to note that the shift in the XRD peak position can be very small, and may require careful analysis of the XRD data to detect. Additionally, other factors such as the quality of the sample preparation and the instrument calibration can also affect the position of the XRD peaks.
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I have XRD plots for a substance at 10 GPs pressure. I want to compare the data I got to the theoretical XRD pattern at that pressure to see if my peaks line up with the established literature. I know how to use VESTA to generate the pattern at different energies but I need to do it for different pressures to compare the peaks.
I do have the cif file.
CHATGPT did not help me so I would appreciate any help.
Simple software like Origin can be used for comparison.
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The existence of anti-phase domain boundaries (APBs) in polycrystalline materials is usually established by electron microscopic techniques (SEM/TEM) [1] and is also discussed in diffraction data analyses.[2]
I don’t have a good familiarity with TEM/SEM (and I’m very open to be educated here) but it doesn’t seem convincing enough to look at some microscopic images with atomic level resolution where APBs are found as a straight line (or arbitrarily curved line as in Figure 7 in ref. 1) forming a boundary/wall between the two domains in the same particles, while there is no disorderliness of any sort around and away from the APB.
The reason I’m raising this point is that particle surface is usually more disordered than any kind of defects in the bulk. In fact, it’s even well established that the surface of solid particles behave more or less like a liquid layer [3], and the smaller the particle size the thicker the liquid layer at the surface. And yet, in the TEM images of nanoparticles that I have seen in some articles there is(are) only the APB(s) visible, and no sign of the bigger unavoidable inherent surface disorder.
Is it possibly due to the fact that in TEM, the electrons pass through the particles and form an image which is influenced by the bulk of the particle? If so, why then the rest of the atomic arrangements within the domains look nearly perfect (i.e. as if it’s a single layer of pointy ordered atoms)?
And as for diffraction data, APBs affect some of the reflections selectively but usually there are different broadening contributions which make it challenging to disentangle. Nevertheless, at least the existence of planar defects like APBs is indicated in diffraction patterns.
Any input would be appreciated.
3)
Thank you for the detailed answer. So, in principle it's possible but challenging.
I'm actually not going to be a TEM operator in the future (I'm not planning to), so I'll not need to know all the experimental problems and considerations. I mainly wanted to know how much I can rely on the data that I see in the literature (I gave a specific reference to an article in the question).
It's good anyways to have general information about it, so thank you for your time.
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How accurate are XRD measurements with Rietveld analysis when compared to other measurement methods in determining the weight fraction of carbon in steel?
Hopefully those experienced with this case would be willing to help.
XRD measurements with Rietveld analysis can be a reliable method for determining the weight fraction of carbon in steel, especially when compared to other non-destructive measurement methods. However, the accuracy of the results depends on several factors, including the quality of the sample preparation, the instrumentation used, and the data analysis procedures.
XRD with Rietveld analysis is a non-destructive method that provides a quantitative analysis of the crystal structure of a material, including the identification and quantification of the phases present in a sample. This technique can be used to accurately determine the carbon content in steel by measuring the lattice parameter of the iron-carbon phase and comparing it to a reference standard.
Other non-destructive methods for measuring the carbon content in steel include optical emission spectroscopy (OES) and X-ray fluorescence (XRF). These techniques are faster than XRD and can provide elemental analysis of the sample. However, they are not as accurate as XRD with Rietveld analysis in determining the carbon content, especially at low concentrations.
Destructive methods such as combustion analysis and gravimetric analysis are highly accurate but require the destruction of the sample, which is not always desirable or feasible.
In summary, XRD with Rietveld analysis can provide accurate and reliable results for determining the weight fraction of carbon in steel, especially when compared to other non-destructive methods. However, the accuracy of the results depends on several factors, and the choice of measurement method should be based on the specific requirements of the analysis.
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I am taking XRD samples at various pressures. I want to compare my sample with established literature.
I know you can download .cif files and view them at different energies using VESTA or mercury, but is there a way to do this at different pressures?
For the simulation of the variation of lattice parameters with the pressure you must know the isothermal bulk modulus and their first derivative; then, use one of the well-known equations of state: Vinet, Murnaghan, Birch, etc. Once the lattice parameter as a function of the pressure were calculated, you can use Diamond, Power Cell, or much other available software for the simulation of the diffraction patterns.
Good luck
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Scholars help me! I have done the Rietveld refinement by using GSAS-II software. How can I plot the refined data in Origin? I have tried many times but I couldn't do it.
Kaushik Shandilya Thank you!
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This the XRD Spectrum of the polymer being carbonized.
Hello,
The X-ray diffraction pattern of a material can reveal information about the crystalline/amorphous structure and phase composition of the materials. In the case of biopolymers, they typically show broad peaks due to the overlapping of different crystal planes within the polymer chains and also because of their semi-crystalline nature whereas, the carbonates, typically show well-defined and sharp diffraction peaks due to their highly ordered structure.
Thus, depending on the relative quantities of the two components and the level of crystallinity in each component, the diffraction spectra in a biopolymer-carbonate composite may exhibit both broad and sharp peaks. The peaks may also show shifting or broadening due to the interaction between both components in the composite. Based on this spectral analysis, one can determine the information regarding the phase composition and crystalline structure of the material.
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Dear all,
Let's say we have a cubic Si (111) substrate, and I choose (100) plane to do the phi scan, how many peaks can we expect to observe?
My instinct tells me there shoud be 4 peaks for a cubic structure, but in reality there is three peaks, each peak appears every 120 degrees
You are correct that a cubic structure should have four equivalent (100) planes. However, when performing a phi scan with an incident X-ray beam perpendicular to the (111) plane of a cubic Si substrate, you would only observe three peaks for the (100) plane at 120-degree intervals.
This is because the (100) planes are rotated by 45 degrees with respect to the (111) plane, so the X-ray beam will diffract from each (100) plane at a different angle, resulting in three distinct peaks in the phi scan. These peaks will be separated by 120 degrees because the (100) planes are oriented at equal angles with respect to the (111) plane.
So in summary, you should expect to observe three peaks in a phi scan of the (100) plane of a cubic Si (111) substrate, each peak appearing at 120-degree intervals.
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In single-crystal neutron scattering or X-ray diffraction, what could be the practical reason that in some cases, equivalent Bragg peaks, such as (2,0,6) and (0,2,6), (1,1,0) and (1,-1,0), have significantly different intensities?
I come across a case where (2,0,6) peak intensity is only half of (0,2,6), but (2,0,6) has similar intensity as (-2,0,6). Looks like something along K direction.
Impurity or defects are ruled out based on sample purity check. What else could be? Multi-domains (with different orientations)? Preferential orientations (this one usually happens in powder)?
Dear David Hu ,
There could be several reasons why equivalent Bragg peaks in single-crystal neutron scattering or X-ray diffraction have significantly different intensities. Some possible reasons are:
1. Anisotropy in the crystal structure: If the crystal structure is anisotropic, it can affect the scattering of neutrons or X-rays in different directions. This anisotropy can cause some Bragg peaks to have higher intensities than others, even if they are equivalent.
2. Multi-domains with different orientations: If the crystal contains multiple domains with different orientations, the Bragg peaks from different domains can interfere with each other, causing some peaks to have higher intensities than others.
3. Preferential orientation: In some cases, crystals can have a preferred orientation, particularly in powder samples. This orientation can cause some Bragg peaks to have higher intensities than others due to the alignment of the crystal planes with the incident beam.
4. Kinematic effects: In some situations, the kinematic scattering theory may not be applicable, and dynamic effects such as extinction or absorption may come into play, causing different peaks to have different intensities.
5. Experimental factors: Finally, experimental factors such as sample misalignment, beam divergence, or detector sensitivity can also affect the peak intensities.
In your case, it's possible that the difference in intensity between the (2,0,6) and (0,2,6) peaks is due to anisotropy in the crystal structure, while the similarity in intensity between the (2,0,6) and (-2,0,6) peaks could be due to the crystal's symmetry. However, without additional information about the crystal structure and the experimental setup, it's difficult to say for certain what the underlying cause of the intensity difference is.
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I have calculated the crystallite size from my XRD data by using Debye Scherre's approximation. Is it necessary to calculate the percent error?
It's Scherrer equation only and erroneous to call it Debye-Scherrer as mentioned by Alan F Rawle. Please see following article for detail:
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how much amount of CNTs needed for SEM, EDS, XRD, FTIR, TGA? how to find out purity of CNTs using TGA?
The amount of sample required for SEM, EDS, XRD, FTIR, and TGA analysis of carbon nanotubes will depend on the specific experimental conditions and the sensitivity of the instruments used,
• SEM: For SEM analysis, a very small amount of sample is required, typically in the range of a few milligrams or less.
• EDS: For EDS analysis, the sample size can vary depending on the desired spatial resolution and the sensitivity of the instrument. Generally, a sample size of a few milligrams or less should be sufficient.
• XRD: For XRD analysis, a larger sample size is typically required, in the range of 10-100 milligrams or more, depending on the instrument sensitivity and the desired level of detail. The sample should be finely ground and homogenized before analysis.
• FTIR: For FTIR analysis, a small amount of sample is typically required, in the range of a few milligrams or less. The sample can be dispersed in a suitable solvent or pressed into a thin film for analysis.
• TGA: For TGA analysis, a larger sample size is typically required, in the range of 10-100 milligrams or more, depending on the instrument sensitivity and the desired level of detail. The sample should be finely ground and homogenized before analysis.
Important Note
The specific amount of sample required may vary depending on the specific experimental conditions and the sensitivity of the instruments used.
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Why are some cementitious products caused by soil stabilization or geopolymerization observed in the SEM micrographs, whereas they are not found in the XRD analysis? For example, many articles have clearly shown the formation of CSH or CAH gels in SEM images, however, these gels have not been seen in their XRD graphs. Note that some articles have indicated the formation of these gels in both analyses.
I did some research. There could be several reasons why cementitious products observed in SEM micrographs may not be detected in XRD analysis, even though both techniques are commonly used to study cementitious materials:
1. XRD analysis is a bulk technique that provides information about the crystal structure and mineral phases present in a sample. It can detect the presence of crystalline phases with high sensitivity, but it may not be able to detect amorphous or poorly crystalline phases such as gels or short-range ordered materials that may be present in cementitious products. On the other hand, SEM can provide high-resolution images of the surface morphology and microstructure of the sample, allowing for the direct observation of these amorphous or poorly crystalline phases.
2. The formation of some cementitious products, such as C-S-H gels or calcium aluminate hydrates (CAH), may occur at a nanoscale level, and their presence may not be detected in XRD analysis due to the small size of the crystals. SEM can provide images with much higher resolution, allowing for the visualization of these small structures.
3. The sample preparation techniques for SEM and XRD analysis can be different, which can affect the detection of certain phases. For example, sample preparation for SEM typically involves coating the sample with a conductive material, which can alter the surface chemistry of the sample. XRD analysis requires a powdered sample, which can cause changes in crystal size and shape, and may also lead to the loss of amorphous or poorly crystalline phases that are more sensitive to sample preparation conditions.
4. It is also possible that the cementitious products observed in SEM images may not actually be the same as the crystalline phases detected by XRD analysis. This could be due to differences in the chemical and physical properties of the phases, or to the fact that they are present in different parts of the sample.
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In my case: LiBH4 - LiBr in different molar ratio.
I have the observed patterns (measured by XRD technique) for this mixture of compounds but I don't have .cif file or any reference to compare the calculated patterns.
I have already done Rietveld Refinement for individual compounds, i.e. LiBH4, LiBr
You can refer to our work, in which we have defined the LiBH4-LiBr phase diagram, for the identification of the phases. You can then find the cif file of the hexagonal LiBH4 and modified, inserting also the Br- anion inside the structure. There are all the indications needed here:
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For XRD analysis
JCPDS does not exist. Now it is ICDD (International Center for Diffraction Data). It's commercial. Data file(s) are not freely downloadable. To get access, subscription/membership/etc might be required.
I do not know which data file(s) you need, but references from the literature can be used to support your results. Also, labs specialized in XRD may help with data files and analysis, since they may have access.
There are many discussions and answers on this topic on RG, that might be helpful. See below:
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How to find out residual stress from XRD data
Residual stress in a material can be determined from XRD data by measuring the lattice strain induced by the stress. The lattice strain can be calculated using the Bragg equation and compared to the strain-free lattice spacing to determine the residual stress.
Here are a few references that discuss methods for determining residual stress from XRD data:
1. Leoni, M., et al. "Residual stress measurements in thin films by X-ray diffraction: a review." Materials Science and Engineering: R: Reports, vol. 123, 2018, pp. 1-55.
2. Noyan, I. C., and Cohen, J. B. "Residual stress: measurement by diffraction and interpretation." Springer Science & Business Media, 1987.
3. Chung, K. "Residual stress measurement using X-ray diffraction and neutron diffraction." Comprehensive Structural Integrity, vol. 7, 2003, pp. 187-224.
4. Kral, M. V., et al. "Residual stress determination in thin films using X-ray diffraction and FEM modeling." Materials Science and Engineering: A, vol. 373, no. 1-2, 2004, pp. 239-244.
5. Cullity, B. D., and Stock, S. R. "Elements of X-ray diffraction." Prentice Hall, 2001.
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Hello,
I have poly-crystalline materials.
When I measure XRD (in and out-of-plane), I obtained several peaks.
it is not matched with well-known crystal structure.
I also obtained the FFT pattern by TEM to determine the lattice spacing.
How can I determine the crystal structure, and orientation such as (111) (100)?
Determining the crystal structure and orientation of polycrystalline materials can be challenging, but here are some steps that you can follow using both TEM and XRD:
1. Analyze the XRD pattern: Obtain the XRD pattern for your sample, both in-plane and out-of-plane. Analyze the pattern to identify the peaks and their positions. Compare the positions of the peaks with the known diffraction patterns for different crystal structures. If none of the known structures match your pattern, your material may have a unique crystal structure.
2. Analyze the TEM image and FFT pattern: Obtain a TEM image of your sample and analyze it to determine the grain size and morphology. Use FFT analysis to determine the lattice spacing and crystallographic orientation of the grains.
3. Combine the XRD and TEM results: By combining the XRD and TEM results, you can determine the crystal structure and orientation of your polycrystalline material. Use the lattice spacing and orientation information from the TEM FFT pattern to identify the diffraction peaks in the XRD pattern. By comparing the peak positions and intensities with those of known crystal structures, you can determine the crystal structure of your material. The orientation of the grains can also be determined by comparing the diffraction patterns from different grains.
4. Refine the structure: Once you have determined the crystal structure and orientation, refine the structure using Rietveld refinement or other methods to obtain more accurate lattice parameters and atomic positions.
It's important to note that this process can be iterative and may require multiple iterations to refine the structure and orientation. Additionally, if the material has a unique crystal structure, it may be necessary to use other methods such as electron diffraction or synchrotron X-ray diffraction to obtain a more accurate determination of the crystal structure.
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I am using jade software to analyze the XRD pattern of a composition with Polycaprolactone. But I cannot find the PDF card of PCL when using Search/Match function. Could anyone tell me the number of PDF card of PCL for XRD analysis? I would be more than grateful :)
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Why we always take 2θ in degree in the XRD pattern. why we not take into radian of XRD pattern?
I think it is due to historical reasons.
Reading of angles in degree(s) is more catchy than in radians; at least for me...
Best regards
G.M.
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can we do XRD ?
Saikat Saha The end application(s) will dictate those properties that are important (Product Performance Predictors or Critical Quality Attributes). For example, in catalysis the specific surface area may be a vital property. This also may be an important property for moisture uptake. Start with the data sheet (for example attached) and see what the manufacturer has measured or defined.
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My goal is to counter-check my SEM photo against my XRD data, which the latter (XRD) confirms that I had an almost spherical particle in nanosize scale.
I think my sample is still aggregated in my SEM, could help describe it?
Thank you
Morphology, as seen, can be identified as spherical with defects. However, one important noticeable point is Packing Density. It's very well with the above image, and the material should be having good charge transfer properties.
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I am analyzing XRD pattern of PrBaMnO. my question is can we compare the peaks that have some shifts from original XRD JCPDS cards? Actually my peaks not matching with any card?
What kind of a peak mismatch is it exactly? If there is a consistent 'constant' shift of all the peaks (to the left or right) compared with the reference, then it's simply a 'zero shift' (meaning your 0 point on the x-axis is misplaced in the process of digitizing your data) and this you can simply manually zero shift (i.e. add or subtract some value from the entire 2theta column) by the right constant value to arrive at a match with the standard.
Otherwise, it could mean that your sample is not pure and there are foreign ions present in your structure (e.g. your sample is doped with something else) or it could even be that you have synthesized a different phase.
Only more specific details can help us understand the problem.
Best regards,
Jamal
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For sintered 18Ni300, under the sintering condition of low vacuum degree, the grain boundary is oxidized. The attachment is XRD and EDS test result. Is the darker second phase mainly Fe2TiO4?
With EDS make spot analysis (not maps), it will clarify the picture.
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Hello
I have the geochemical data of the XRD and ICP analysis of the lake sediments and have to draw a graph to analyze them. I think Excel charts are not very attractive. What other software can I use?
thanks