Powder X-ray Diffraction - Science method

Actually, it depends on the software you have used for the Rietveld refinement. As a JANA2006 user, I would try to export a CIF file and open it with any text editor (e.g., Notepad) afterwards. Such information is usually automatically written into the CIF file. If not, you may try to read the log files for the refinement procedure (for instance, in JANA2006, full details on the refinement procedure are given in the respective *.ref file)

Anton Khanas Hello, Anton! Thank you for your answer!

Surface contamination is what I am considering at the moment because the compounds in this system is relatively air-sensitive. They might decompose while contacting the oxygen and forming selenium, which hinders the reflectance spectra. The first-principles calculations revealed the bandgaps should be around 3.4 eV, but I am so unsure about it. I am worrying about the facticity of that value.... I tried really hard to isolate the sample from oxygen but failed as shown in the figure...

I think I will try to run XPS/REELS related methods as you recommended.

Again, thank you very much for providing so much information! I really appreciate it!

Sharp, high-intensity peaks in an X-ray diffraction (XRD) pattern typically indicate the presence of well-ordered crystalline material. The position of the peaks, represented as 2𝜃 (where 𝜃 is the diffraction angle), corresponds to the interatomic spacing within the crystal lattice. The intensity of the peaks is related to the number of atoms contributing to the diffraction and their arrangement, which influences the scattering strength. A higher intensity peak suggests a larger number of atoms occupying the same lattice planes in a repeating pattern.

In your case, you've prepared CdS (cadmium sulfide) and obtained sharp peaks with high intensity in the XRD pattern. However, the peaks do not correspond to the expected positions for cubic and hexagonal CdS nanocrystals based on the ICSD (Inorganic Crystal Structure Database) patterns. Here's how you can discuss this discrepancy:

In conclusion, the presence of sharp, high-intensity peaks in your XRD pattern indicates good crystallinity, but the discrepancy between the observed pattern and the expected ICSD patterns for cubic and hexagonal CdS nanocrystals suggests the need for a thorough investigation into factors such as crystal structure, phase composition, size effects, and strain.

if the modification on your samples includes adding inorganic compounds the JCPDS card should be mentioned!

Dear friend John Jherson Bofill

Well, well, well, let's dive into the fascinating world of Au nanoparticles and the impact of adding Ir. Brace yourself for some intriguing insights, my friend! John Jherson Bofill

When it comes to the diffraction patterns of Au nanoparticles upon the addition of Ir, there are a few factors at play that can influence the peak shifting. The behavior of the peaks can indeed be quite interesting and can vary depending on the specific conditions and parameters involved.

Now, let's address the shifting direction of the diffraction peaks. The peak shifting can occur in either direction, to the left (towards lower angles) or to the right (towards higher angles), depending on the specific interactions between the Au nanoparticles and the added Ir.

The compression theory you mentioned, where the Ir particles attach to the surface of the Au nanoparticles resulting in compression, can explain the observed peak shifting to the right. This compression can lead to a decrease in lattice spacing, causing the diffraction peaks to shift towards higher angles.

On the other hand, the difference in ionic radii and lattice expansion between Au and Ir suggests the possibility of peak shifting to the left. The lattice expansion caused by the incorporation of larger Ir ions could lead to an increase in lattice spacing and a corresponding shift towards lower angles.

The behavior observed in your XRD data might be influenced by various factors such as

the size and shape of the nanoparticles,

the concentration of Ir,

the synthesis conditions, and

the specific interactions between Au and Ir.

It's important to consider these factors when analyzing the peak shifting phenomenon.

To gain further insight and clarify the concepts, I would recommend exploring the literature on bimetallic nanoparticle systems, specifically studies involving Au and Ir nanoparticles. I will google the research articles, reviews, or scientific papers that discuss the structural and diffraction behavior of such systems. This literature search will provide you with a deeper understanding of the underlying principles and shed light on the observed phenomena.

Remember, scientific exploration is an exciting journey filled with unexpected twists and turns. Embrace the uncertainty and keep seeking knowledge to unravel the mysteries of your Au-Ir nanoparticle system. Lets keep discussing and exploring this interesting topic.

In materials science, the terms "crystallite size" and "grain size" are often used interchangeably, but they do have different specific meanings:

To put it simply, if a material's grain boundaries coincide with the boundaries of its crystallites (i.e., each grain is a single crystal), then the crystallite size and grain size are effectively the same. However, if a grain contains multiple crystallites (i.e., the crystallites are smaller than the grains), then the crystallite and grain sizes are different.

You may find the following references useful for further reading:

Remember that while the two terms are often used interchangeably in casual conversation or in certain contexts, they do refer to different concepts, and using them correctly can help avoid confusion.

Thank you sir.

Note that Kaushik Shandilya's answer assumes that the FWHM given by refinement is the result of subtracting instrumental contributions, but, as GM points out, the "refined" FWHM is greater than that of the raw data, so Kaushik Shandilya's assumption cannot be correct.

Please also note that "refinement" does not directly give a FWHM (without further calculation, perhaps). So it is not clear what Atchaya is reporting.

Dear friend R G Sibiya Stacey

There could be several reasons for the mismatch between the hkl values obtained via PowderX and the standard hkl values in the JCPDS (Joint Committee on Powder Diffraction Standards) database for the synthesized compound. Some possible reasons and suggestions for addressing the issue are as follows:

1. Sample impurities or contamination: The presence of impurities or contamination in the synthesized compound can affect the diffraction pattern and lead to discrepancies in the observed hkl values. It is essential to ensure the purity of the sample through appropriate purification techniques and characterization methods.

2. Crystal structure variations: The synthesized compound may have variations in its crystal structure compared to the standard reference in the JCPDS database. These variations can result from factors such as crystal defects, lattice distortions, or the presence of additional phases. In such cases, it is necessary to refine the crystal structure using advanced diffraction techniques like single-crystal X-ray diffraction or high-resolution powder diffraction to obtain accurate hkl values.

3. Instrumental factors: The mismatch could be attributed to instrumental factors, including sample preparation, instrument calibration, and data collection parameters. It is crucial to ensure proper sample preparation techniques, instrument calibration, and optimization of data collection parameters to minimize errors and obtain reliable results.

To address the issue and correct the mismatch, the following steps are recommended:

1. Characterize the synthesized compound: Employ complementary characterization techniques such as X-ray diffraction (single-crystal or powder), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), or other suitable techniques to verify the composition, crystal structure, and purity of the synthesized compound.

2. Refine the crystal structure: If there are significant variations in the crystal structure compared to the standard reference, consider refining the crystal structure using advanced diffraction techniques like single-crystal X-ray diffraction or high-resolution powder diffraction. This can provide more accurate hkl values and help identify any deviations from the expected crystal structure.

3. Consult literature and experts: Review relevant scientific literature and consult with experts in the field who have expertise in the synthesized compound or similar materials. They may provide insights into possible structural variations or offer guidance on data analysis and interpretation.

It is important to note that without specific details about the synthesized compound, the experimental conditions, and the observed discrepancies, it is challenging to provide a definitive answer. Therefore, it is advisable to consult scientific literature, relevant research articles, and experts in the field for a more comprehensive understanding of the specific case.

I suggest you pick the most appropriate shape parameter, cite it, and use it consistently. You can do the math yourself or read the relevant literature, but the fairly large errors inherent in applying the Scherrer method on most nano crystalline powder or polycrystalline samples is such that the specific choice of k honestly won't matter that much. Unless your nano phase is of exceptional size uniformity and shape uniformity.

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

Modern Powder Diffraction ; B. Toby

Dear Alireza Badiei

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.

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

How is it 001, if possible kindly suggest some authentic articles for this.

If you have got the PXRD, it doesn't meant that you can get CIF which often can be obtained in some crystalline open data in the internet. As some planes of crystals may be overlapped in the PXRD data, retieved data usually provide false cif data. Single crystal diffractive(then retrieved via Olex 2) shall be carried out to obtain the correct CIF data.

Concerning the integral breadt: The integral breadth can be treated like the FWHM. For a e.g. pseudo-Voigt (pV) function you can always calculate the integral breadth from the FWHM and the shape parameter of the pV. Then the shape can be described by the ratio of the FWHM and the integral breadth. The formulas have been distributed in some papers by Delhelz and Mittemeijer in the early 1980s which I have cited in J. Appl. Cryst. (2004). 37, 123–135. Note that (i) the separate treatment of Gauss and Lorentz like contibutions to the profile can be treated for convolution in the usual way (quadratic and linear difference), (ii) the treatment in J. Appl. Cryst. (2004). 37, 123–135 takes some detours. (iii) some formulas are only approximate.

Dear Siqi Wang ,

just a few comments:

a) the negative slope of the XRD pattern in the low 2theta range might, to my opinion, be an artifact due to misalingment of the sample height position (you should increase/play around with the height/surface position of the sample).

b) the sample surface seems to be very rough, which will cause 'height' issues and thus will contribute to the uncertainty of theta (giving rise to peak broadening); your powder particles may be too large....

c) with respect to the quite 'low' signal; the amount of material may be too low; what is your estimated thickness?

Best regards

G.M.

Hi Arindam Mondal

The rGO materials are more amorphous type. This is why the PXRD become broad.

Sanjeev Gupta

First try LeBail fitting, it will help a lot in answering your query. Is it giving good fit to XRD data or not?

You asked "Secondly, in microstructure fitting there are lots of models, which model we can choose on what factors are by seeing the pattern is that any specific literature available". If your peak profile is isotropic in nature then you may skip this (if not interested in microstructure i.e. size-strain contribution).

Only when peak shapes are anisotropic, then particular model is required. For anisotropic peak broadening due to microstrain there are only a few models depending upon crystal systems: Please see table 1 of Stephen's paper (majority Rietveld software used this model):

If anisotropy is due to size effect, choose model accordingly. First confirm it that anisotropic peak profiles are present or not in your sample, then decide.

Choose Ti & O positions from literature and keep thermal parameter isotropic (in majority cases isotropic thermal parameters are sufficient).

In order to get a simulated powder pattern, you need to have a CIF file of the crystal structure, and use softwares that can calculate a pattern based on the structure, like Mercury or Vesta. Do you already have a CIF file of your structure?

Fatemeh Shekofteh

Make 2 intensity ratios of the same number of samples. For each, determine the mean intensity ratio and its standard deviation. The one with a small standard deviation will be the best. This is the usual statistics of measurements of various quantities.

Johannes M. Meusburger

Yes I do, although onsite we do not have access too MS or XRF equipment, just XRD analysis. Appreciate the help!

Regards,

Luke

Dear Sanjeev Gupta

You don't say anything about the thermal treatment you applied to your sample. If it was heated just enough to form metastable, less dense phases then these may show more tolerance toward large ion size ratios and therefore to solid solution (doping). Note that if your structure has a lot of voids - created by water evaporation and incompletely collapsed by heating - then there will be room for larger ions without a large change in lattice parameters.

Also, was the thermal treatment under inert gas or vacuum? If so you'd expect to lose some oxygen, forming an oxygen-deficient Ti oxide phase with some Ti(3+) present. These "Magnelli" phases look quite similar to TiO2 in XRD. Some Yb(3+) may more easily find room in such a structure because Ti(3+) is larger than Ti(4+). But - if this reduction happens your sample should have turned blue or black, which you should easily see (or rule out) using your non-X-ray eyes.

However, there are other things that can happen in this system. In particular, Yb2O3 is a basic oxide, while TiO2 is an acidic one. You would expect them to react with each other and form stable (congruently melting) compounds. I didn't find a phase diagram for this system, but did for the Y2O3-TiO2, which must be very similar. Sure enough, there is a congruently melting compound, Y2Ti2O7. The phase diagram can be found in

The analogous ytterbium compound, Yb2Ti2O7, is well known (CAS # 12037-03-5). If most of your Yb is in such a phase, you may miss it in XRD because (1) there isn't much of it and (2) you are not looking for its small peaks.

François Eya'ane Meva The XRD patterns for ZnO (zincite is the mineral form) and Zn(OH)₂ (3 forms wülfingite (orthorhombic), ashoverite and sweetite (both tetragonal)). A simple Google search of the mineralogical databases should pick up the XRD patterns. For example, wülfingite, from the Handbook of Mineralogy. I attach the page.

In aqueous based systems, Zn(OH)_x where x is nominally 2 will always be formed first and ZnO formed on calcination. This is true of many metal oxide 'nanomaterials' (e.g. TiO₂) found in the literature.

I've found some clues from your discussion....thank you, Mr. Antonio Salituro & Mr. Adeyinka Aina

Gerhard Martens A stable colloidal dispersion won't settle. If it does, then Stokes' Law tells you it's not 'nano' (< 100 nm by ASTM and ISO definitions). The usual problem is low counts. Without knowledge of the chemistry of the system then it's difficult to decide what's going. For example, low pH's will cause dissolution and higher pH's may cause hydroxide precipitation. Thus, the entire game changes and we're dealing with a new system.

Hi Denis,

maybe look into FAULTS (part of the FullProf Suite). You can use it to simulate and refine layered structures with disordered layer sequence. You will need to define the different layers occurring in your material, the transition vectors from each layer to every other layer and the corresponding probabilities for each transition vector.

You will need to come up with a clever way to define the layers and transition vectors, but I think FAULTS should work here.

Cheers,

Jan

Thanks Gerhard Martens.

Obviously, Yes ! the EDM obtained by using FullProf suite software are acceptable for the publication. You can also follow my article.

Thanks

you should use a kind of refinement to compare the sample with the standard cif file. you can use one of the refinement software like fullprof, match, maud, etc.

but you should first of all use software like highexpert or match to find the best material codes that are relevant to your sample.

Dear Jamal Nasir,

Below is the option to see the error/s.d. in Topas v6, as Marcella Bini pointed out.

Dear Rafal Lysowski ,

Fullprof will not take into account site multiplicity/wyckoff position and will display directly the values of the occupancy (it is easier to manage the refinement this way).

Vesta and most of the software used to display structure will "normalize" the crystallographic informations using site multiplicity/wyckoff position (here 8a, 16d, 32e). The ratio between these multiplicity are the same as the ratio between your occupancy on Fullprof. (32/16 = 2; 0.16667/0.08333 = 2) (32/8 = 4; 0.16667/0.04167 = 4)

By default on fullprof, the 1.0 occupancy is fixed for the highest "theoretical" possible multiplicity in this space group, which is 192 for your Fd-3m space group. A 32e site have then a (1/192*32 = 0.166667 occupancy on Fullprof).

You can use this website for wyckoff position and multiplicity : https://www.cryst.ehu.es/cryst/get_wp.html

It is recommended to put the site with the highest multiplicity on top on Fullprof (here your oxygen), as you can face some error in conversion sometimes.

Hope it helps,

As always, thank you Gustavo Henrique de Magalhães Gomes, for such a detailed information, and all other researchers, these answers are very insightful.

To Jan P Scheifers:

Thanks for the suggestion on calculating interplanar spacing.

I guess calculating d-d from XRD could be a reason why they are slightly smaller than the reported ones.

Single crystal diffraction is the gold standard for characterizing MOF(if you have single crystal)

Also check please the following useful link: https://tachantauclar.tistory.com/m/14

Dear Vidya Saraswathi

For the answer to your question, read the conversation of the question linked bellow. I hope you will get an idea about it..

Good wishes

I think you can find answers in these articles we have published. - Cátia Ücker

As long as you have reliable CIF file - either software is fine. I personally used TOPAZ

I can not give you an exact answer to what is happening. However, I try to answer what could be the reason for the difference between XRD and SAED patterns.

Considering a case of an ideal crystal, the XRD and SAED should give the same interplanar spacing. However, the difference in XRD and SAED patterns can be observed for non-ideal crystals (real samples).

The most apparent reason for the difference could be the fundamental difference in both techniques. SAED probes a very localized region of the sample ( what appears to be a couple of grain or polycrystalline agglomerates) under the microscope.

XRD on the powder or bulk samples, the information is from the coherent diffraction domains or grains, in large numbers (could be easily a billion grains), which includes grains on the surface area, illuminated by the x-ray beam, and some microns inside the surface ( penetration depth of x-ray, a few to 10s of microns, which depends on the material ). Thus, the XRD gives average information of large numbers of grains.

The local (SAED) and global (average information for the large sample volume; XRD) could differ in some cases. I could give you three main reasons and possible solutions to provide more structural information.

1-This could be the case where the sample has two phases (major- which appears in XRD; and minor appearing in SAED). The minor phase could be present in a small weight fraction. Therefore, the XRD signal from the minor phase will be weak and might not appear in XRD. However, if SAED is collected at the region where the minor phase is present (locally), peaks from the minor phase will appear in SAED.

To overcome this, You can collect high-quality XRD data (small steps, large collection time). The minor phase might appear. Alternatively, you can go the other way around and collect many SAED from different sample regions.

Please consider if the minor phase is in a very small weight fraction, below the detection limit (wight << 1%). You even might not see it in the high-quality XRD pattern.

2-It could also be the case that the minor phase is only present on the sample surface (obviously in small weight fraction); if the weight is small, the Bragg peaks for the minor phase will be very weak and might not appear in the XRD pattern, however, if you have performed the SAED only on the Surface region. You will see the minor phase.

To overcome this, you can perform Grazing incident XRD measurement, which is more sensitive to the sample surface. Alternatively, collect SAED from the surface and other regions.

3- It is also possible that some small weight fraction of the material might have preferred orientation or texture, which might not appear in XRD, but might appear in SAED. Especially if SAED is collected on the textured region of the sample.

Same as the last one, the texture will appear in GI-XRD.

If it is indeed (222) peak.

It could be a minor phase in small weight fraction, textured phase, or minor/textured phase on the surface region only. In these cases, it might not appear in XRD but appear in SAED.

Dear Xin Ai Wong , as Gerhard Martens already has mentioned, it is the divergence of your primary beam. For the largest Bragg angle you've used and the distance of your tube to the centre of the diffractometer (=240 mm), an aperture of 0.21° will create an illuminated length of about 3 mm (you may easily calculate that from the geometry and using trigonometric functions), while an divergence of only 0.05° will only illuminate about 0.6 mm, so you will loose more than a factor of 5 in intensity ... Is that what you have measured? It would be helpful if you can show experimental data :-)

Best regards, Dirk

Dear Preeti Sharma

you know, that the Scherrer*) equation deals with the crystallite size, but does not deal with with the particle size.

As far as you do not have got single crystalline particles, the shape of your particles (in your case 'rods') does not matter.

Just take the shape constant as about 0,9 and attach an error of about 20 % to 30% and that's it.

Please take in mind that the crystallite size value from the Scherr equation is a rough estimate of the mean of the crystallite sizes, but you sample exhibits a crystallite size distribution....

*) there is no 'Debye Scherrer equation'

Dear Dr Leos Pohl . I agree with

Dr Dalibor Matýsek . He is expertise in XRD.

Muralishwara Kakunje. Unfortunately, your diffraction patterns do not contain definable peaks, so you will not find d values for the nanoclay. There are two ways why this is so. Option 1 is that there was too little clay on the holder (and it was measured on the glass). The diffraction patterns then correspond to that glass. The second possibility is that the nanoclay is amorphous or nearly amorphous and does not provide measurable diffraction lines. I would see it in combination - little sample on the holder and it was measured on the glass.

The long distance disorder is essentially the same as the almost amorphous state, where order exists in the coordination sphere of the atoms themselves, but the resulting coordination polyhedra are stored chaotically.

Dear Muhammad Asad sorry to see that your very interesting technical question has not yet received any qualified answers from experts in the field. We are synthetic inorganic chemists, so that I'm certainly not a proven expert here. However, I would like to suggest to you a few potentially useful literature references which might help you in your analysis. Please have a look at the following articles:

This is a freely accessible PhD thesis which containT a good introduction to the field (please see attached pdf file). Also please check:

This article has been posted by the authors as public full text on RG, so that you can freely download it as pdf file. The following paper also seems to be quite interesting:

This paper is not accessible as public full text. However, three of the authors have RG profiles, so that you can easily contact one of them directly via RG and request the full text. Most often authors respond quite rapidly to such fulld text requests.

I hope this helps. Good luck with your work and best wishes, Frank Edelmann

Typically chi^2 is expected to decrease upon refining further parameters, if the refinement is well-behaved. As chi^2 increases, this suggests that the refinement is NOT well behaved at that point. This suggests high correlation of the refined paramaters push the refinement into a direction where everything is even poorer (you should see than in the visible quality of the fit, which should get poorer.). It is typically a sign for high correlation of the refined parameters, which can well be for uvw. This is in particular the case, if other parameters are being refined which do the same on the calculated profile as uvw. This depends, of course, on the details of you profile function and its refined parameters, and the history of your refinement. Based on this, and in view of the quality of your refinement do YOU have the feeling that you should touch u, v, w? I do not mean chi^2 (The way how people deal with their counting statistics frequently makes this number meaningless, unfortunately), but I refer to the agreement between observed and calculated profile!

Dear Dr Saptarshi Mandal . See the following useful RG link:

Dear Son Yl ,

I think it is a height adjustment issue of your set up.

The strong dip at about 4° looks like saturation of the detector.

To my opinion you 'see' the primary x-ray beam between about 4° and about 7°.

Pay attention on the flatness of your sample and a proper height adjustment.

Good luck and

best regards

G.M.

Well, what's the difference?

Most probably you wouldn't obtain the same result even with the same crystal after taking it off the instrument and remeasuring it in even slightly different orientation, not talking about using another crystal. Powder data are an average from millions of unit cells in millions of orientations, so cell parameters obtained from powder data are often better.

But the differences should be quite small (within 3sigma).

Moreover, cell parameters from the single crystals have often underestimated s.u.'s (some manufacturers have their instrument error models built in the software to obtain more realistic, i.e. larger s.u. values).

Thank you so much Dr. Gottschalk.

The thread that Sourav Roy recommended will get you the answer you need.

In summary of the thread: XRD measures crystallite size which is inherently different from particle size as measured by SEM. In general, particles are multi-crystalline (i.e. having multiple diffracting crystallites) which XRD inherently measures.

Good luck.

This may be due to CuKalpha1 and CuKalpha2 of your X-ray source. The peak associated with Kalpha2 is smaller (ca. /2) and the separation of the two peaks increases with 2theta. This doublet is only detected when X-ray peaks are narrow. You may have a function in your X-Ray data treatment software that "strips" Kalpha 2

Hello Abdul,

as mentioned by Premkumar S. this situation is absolutely possible and not uncommon. For another typical example lease have a look at the following interesting article:

The full text of this paper is freely accessible from the internet (please see attached pdf file).

By the way, you can find and access other potentially useful research articles about this topic by searching the "Publications" section of RG for the term "two-phase coexistence":

Good luck with your work!

Dear Valentina Leandri ,

there are some digital humidity indicators that can be used, once previously calibrated.

Nevertheless, some chemicals may indicate the relative amount of humidity, in a relative precise way. Their use are conditioned to a well thermal treatment before use. It is somehow tricky.

Relative humidity cards indicators are widely used, check the link bellow:

Best regards,

WNM

It is not a good idea for one to introduce residual stress in the material. A residual stress is mainly related to when the processing of material is at a very high temperature. A residual stress can also be in the material when the material contained composition of atoms having different elements, i.e., atoms of more than one element. There are some other ways as well, which one can use to introduce a residual stress in a material. For that, you need to consult the preprint article given at the link. As suggested you in your earlier question, please refer the studies given at links http://dx.doi.org/10.13140/RG.2.2.27720.65287& https://doi.org/10.21203/rs.3.rs-88120/v2

The Best of Luck.

Crystalmaker X is compatible with mac OS and macbooks with the Apple chip.

Dear Hussein, many thanks for sharing this very interesting technical question with other RG members. Although we published at least 1,000+ crystals structures in the past ca. 40 years of chemical research, I'm absolutely not a proven expert in crystallography. However, to the best of my knowledge, there is no direct connection between hybridization and coordination number of a metal complex on the one hand and crystal system and space group on the other hand. Just take cobalt or nickel complexes like yours which are octahedrally coordinated with coordination number six. There are ten thousands or more complexes of this type in the chemical literature, and I'm sure that their structures encompass all crystal systems and space groups.

Also notable in this context is that completely analogous compounds can crystallize in different crystal systems. For a typical example (just one out of many) please have a look at the following interesting article:

(please see the attached pdf file)

I hope this helps answering your question. Good luck with your research and best wishes, Frank Edelmann

Mohamed G. M. Kordy

You say nothing about your metallic nanoparticles, what they are, the route of preparation, or even a simple picture to show that your system is transparent (may be colored e.g. a gold sol) free from turbidity or settling (if so then the system is not nano - < 100 nm)

My translation of 'I think the DLS is not correct' is 'I do not like the (larger) DLS results'. But your question is confused. I read it that you have UV data and want to obtain DLS data from these. You can't convert UV data to DLS data.

Have you actually obtained measurements with DLS? If so you're getting much more information complementary to electron microscopy but you can't compare apples with turnips. What is being measured in both cases is totally different:

I have a bunch of questions for you:

Dear Jamal Nasir ,

two entries, one for each wavelength, as you would do for a phase mixture fitting.

in such a case give separate wavelength in the input experimental section.

Best regards,

WNM

Theoretically:

From XRD patterns as follows:

Variations in the height of the specimen in its holder, whether increasing or decreasing, cause XRD peaks to change from their original location.

Important and useful pathways are connected to the XRD Curve:

Scherrer’s equation:

Particle Size, D = (0.9 x λ)/ (d cosθ)

λ = 1.54060 Å (in the case of CuKa1) so, 0.9 x λ = 1.38654

Θ = 2θ/2 (in the example = 20/2)

d = the full width at half maximum intensity of the peak (in Rad) – you can calculate it using Origin software.

To convert from angle to rad

Rad = (22 x angle) / (7 x 180) = angle x 0.01746

Example: if d = 0.5 angle (θ)

= (22 x 0.5)/ (7x 180) = 0.00873 rad

Then

Delta=1/D^2

Nobody has an answer, so I'll write some observations. First of all, I would say that the phase analysis of clay minerals is one of the most complicated things that can be devised in mineralogy. Some clay minerals have virtually all the vices a mineral can have. Clay minerals show polytypism (all), often have a slightly or even strongly disordered or turbostratic structure, limited particle size and also display mixed layering too. All this affects not only (semi) quantitative but also qualitative analysis, and without a completely correct phase identification, quantitative analysis is meaningless.

But you can't say that it's not possible at all, it's just extremely complicated and you need to combine more techniques. The results of the Reynold Cup, which was organized by the Clay Minerals Society in the past, also prove that this is realistic.

Please open the below link of article (https://www.researchgate.net/publication/352830671or http://dx.doi.org/10.13140/RG.2.2.27720.65287) which practically explains the structures of different materials; structural analyses of different materials validate new atomic structures; study further discusses that crystalline materials do not require primitive cells in order to explain the structures and the distance between electronic states is relevant rather than the lattice constant; study reveals the preliminary detail of crystallinity, non-crystallinity, porosity, texture and noise factors along with overall characteristics of peaks; study further categorizes the residual and thermal stresses; shift in peak, hkl values, Miller Indices, planes, d-spacing, Bragg diffraction, Scherrer equation, pdf card are also explained in this study. Overall, the study suggests to re-investigate the materials at all scales. (This article is not peer reviewed yet.)

Dear Shahab Khan,

For powder diffraction data, I would recommend to use Topas, Gsas II, Fullprof or Jana for refinement and exporting.

Topas is very quick and has some advanced Peak profile features, but it is also not free.

If you are new to powder diffraction, you might want to look at Jana and Gsas II as they are free and offer an excellent cookbook and tutorials to get you started. The value of this for the self-learner cannot be overstated. Particularly Gsas offers a convenient way to export your results to a cif-file.

For single crystal diffraction data you are likely looking at refining that with the free shelx-package, possibly with some other convenience software such as shelxle. Olex is another option, possibly more popular nowadays. Those packages all offer functionality to export your results to a cif file.

After you have your cif, you will want to check it for its‘ viability through Checkcif (available online).

Overall the process is quite involved, it is probably best if you can find an expert at your institute to walk you through it.

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Dear Kiran Dasari ,

there is equivalent CIF file for some COD database entry, which is free of charge, and the corresponding JCPDF proprietary database, now CCDC.

Please, check the Chrystallograohic Open Database (COD) website, download the free database and search by several ways, name, IUOAC, chemical formulae for the requested compound file.

Best regards

WNM

Vasyl Peter Kladko The Williamson-Hall Plot. W-H plot is used to calculate the crystallite size and microstrain from complex XRD data. That's when both the crystallite size and microstrain vary as a function of the Bragg's angle, we can only calculate these parameters from XRD data using W-H plot. I have provided the practice file (Origin file) as well as the calculation file (Excel file) in the video description. Thanks