Powder X-ray Diffraction

Powder X-ray Diffraction

  • Gert Nolze added an answer:
    After doing Rietveld refinementD pattern, up to what digit I can use significant digit in density Volume?

    After doing refinement up to what digit my data is signify and more appropriate for lattice parameter, density which we got from refinement it is up to two digit after decimal or at 3 digit place because software is giving up to 8 digit and if error is not mention like it shows not refinable or convergence is achieved using software like MAUD or GSAS or Full prof suit.

    Phases: Anatase

    Density: 3.886709467754902

    Qc: 0.039580699022727636


    Density: 4.237931708245432

    Qc: 0.041330379950423025

    - Parameter: Blue P-25.par:Sample_x:Rutile:_cell_length_a Value: 4.5977335, minimum: 5.0, maximum: 30.0 Status: not refinable, onl

    - Parameter: Blue P-25.par:Sample_x:Rutile:_cell_length_b Value: 4.5977335, minimum: 5.0, maximum: 30.0 Status: not refinable, onl

    - Parameter: Blue P-25.par:Sample_x:Rutile:_cell_length_c Value: 2.9612927, minimum: 5.0, maximum: 30.0 Status: not refinable, only

    How can I significantly write it? This is data I got using MAUD.

    Gert Nolze

    Well, this not only depends on the volume bit also on the mass. Only of you know the composition very exact rho=m/V. Have a look at this presentation. All software programs using in their fundamental version the given equations. The scaling and the example of Ettringite should answer your question. For numerous phases, e.g. mixed crystals, unknown crystal water or OH grous, or even as for ettringite the not described  H may change the mass dramatically and so the density.

  • Marcin Nawrocki added an answer:
    Do differences exist between the thin film and powder materials XRD? What are the best methods for examination materials?

    XRD is a method to know the crystalline structure. The materials which be used in substrate deposition it is important to know some parameters about material such that lattice constant , dislocation density and strain.  

    Marcin Nawrocki

    Powder Diffraction gives you a set of reflection peaks using Bragg-Brentano geometry (2Theta-Omega) scan or Debye-Scherrer (2Theta). This technique is used for polycrystalline samples (in flat plate and transmission geometry) and gives you information about structural alteration (atomic coordinates, unit cell parameters, displacement factors, phase to phase ratio). 

    Thin films are usually monocrystalline layers deposited on a substrate by epitaxy, which can be investigated by High Resolution X-Ray Diffraction. In this case you have two different geometries, one is Bragg-Brentano Omega-2Theta and the second one is 2Theta-Omega (requires hybrid monochromator). HR XRD is used to measure very precisely only 1 peak (in contrast to powder XRD, in which you record many) and provides with detailed information about  defects in the crystal structure from the peak shapes. This technique is only used in reflection mode and HR XRD instrumentation can be also used to measure powder samples with 2Theta scans.

    Both diffraction techniques use copper radiation source.

    The main difference between both is that in HR XRD measurement  you need to collect every reflection separately and put them together to obtain a full profile, however the measured peaks are of very high quality and reveal presence of all layers in your thin film sample. By adaptation of e.g. Williamson-Hall method to the HR XRD single peaks you can obtain layer thickness and strain induced by adjacent layers, while in Powder Diffraction you will obtain average crystallite size and micro-strain based on all reflections. In powder samples millions of small crystallites contribute to peak shapes but in thin film samples peak shapes are influenced by number of layers which results in peak splitting (indicating different lattice parameters for each layer) and profile fitting is performed on each peak separately. If you place a thin film sample on a powder diffractometer you will probably record nothing, since the peak widths can be as small as step size.



  • Yanchun Zhou added an answer:
    How can I find the lattice parameter from 2theta intensity data of a ferrite sample?

    Ferrites have inverse spinel structure. I am giving the datasheet in attachment.

    Yanchun Zhou

    FWHM can be directly measured from a peak in XRD pattern plotted in origin.

  • Hyuksu Han asked a question:
    Does 1T-MoS2 transform into 2H-MoS2 phase if irradiated by X-ray ?

    I want to measure XRD on 1T-MoS2 phase, but sinceit is unstable phase I am wondering whether it will transform into stable 2H-MoS2 phase after measurement. 

  • Sadeem Fadhil added an answer:
    What's the interpretation of different EDX results at different directions for metals?

    I got two results which are totally different when applying EDX SEM at two different directions perpendicular on each other for an aluminum metal. What 's the interpretation for such result?

    Sadeem Fadhil

    Dear Ian

    I agree with you, I need to accomplish XRD test in both directions.

    Thank you

  • Dražan Jozić added an answer:
    Is there anyone who can help me to study the silicon standard data?

    I have analyzed the standard silicon using highscore plus:

    1-      Determine background

    2-      Search peaks

    3-      Fit profile

    4-      Fit profile with (asymmetry type :split width and shape)

    5-      Agreement indices ˂10.

    Then as result i find that the Gaussian curve don't follow a Caglioti function.

    Where is the fault and how I can improve my results?

    I take in your attention that the intense peak is not very well fitted, which is due to the soller slit, and I don't know how improve that.

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    Dražan Jozić

    Dear Bendoumia, comments from the Ali Sari are really good. You have some problem with geometry of your setup. I saw some irregular displacement cca. 0,005 degree, after correction of this replacement Rietveld Refinement is pass.

    + 1 more attachment

  • Max Rieger added an answer:
    What free software do you use to analyze XRD data?
    There is many free software to analyze XRD data but what is the best, if I have raw, dat, cpi, sd , rd data?
    Max Rieger

    as far as i know, Match! ist not freeware. 30 day trial is available.

  • Dalibor Matýsek added an answer:
    How can I overcome quartz peak's intensity in bulk mineralogy (powder sediment sample) XRD analysis?

    Powder XRD analysis.

    Dalibor Matýsek

    First it is necessary to define what is the purpose of these analyzes. Sediments usually contain high levels of quartz, that's a fact. After using the separation in heavy liquids as bromophorme can be identified heavy minerals. When is used sedimentation in water (or centrifugation) is possible to identify clay minerals. For clays is used procedure consisting dispersation of the sediment in water with addition of a dispersant (Na4P2O7, max 50-100mg/100g sample) in an ultrasonic bath, sedimentation (time after Stokes law) and then preparing sedimented samples for XRD. Sometimes it is necessary firstly to remove the organic fraction (H2O2), carbonates (citrate-bicarbonate procedure) or Fe oxides (with the Na-dithionide in citrate buffer).

    In some cases, such as is determining of the type of cement in sandstones, is sufficient the screening under 0.063 mm by gently milled sample. 

  • Lawrence Margulies added an answer:
    Can anyone suggest the XRD pattern of precipitate of CuCO3 and hydromagnesite ?

    A recent report on the removal of copper using nesquehonite (MgCO3.3H2O) clearly demonstrated the formation of Cu precipitation as CuCO3 and Cu(OH)2 along with MgCO3. With this idea, we tried to develop stabilization of copper on hydromagnesite [(Mg5(CO3)4(OH)2.4H2O]. The expected product may have the mixture of CuCO3. Cu(OH)2 .MgCO3. Can any one suggest the percentage of contents with corresponding phases in the attached data.


    + 2 more attachments

    Lawrence Margulies

    The low angle peaks have their high angle side clipped. This suggests that a sample size correction needs to be applied to the data to account for the changing footprint of the beam as a function of 2theta. The signal to noise is very poor. Do you have any idea why? If that's as good as it gets I would suggest counting at least 10 times longer.

  • Sanjiv Ravalnath Dharwadkar added an answer:
    Does surface adsorption affect the unit cell volume and XRD peak position?

    Hi all,

    I synthesise crystals in the presence of organic and inorganic additives. Aqueous chemistry analysis shows that there are surface adsorptions and crystal incorporations. Also there are shifts in XRD peak position. Would you please guide me:

    1-  Does surface adsorption affect the unit cell volume and XRD peak position?

    2- If yes, then how can I find out that the XRD peak position shifts relate to the surface adsorption or crystal incorporation?



    Sanjiv Ravalnath Dharwadkar

    All of us know that the X-ray diffraction peaks result from the diffraction from the planes in the crystal lattice.It is necessary that the long range order exists within the material to build up this  periodicity.In the absence of the  periodicity one would not expect to obtain the diffraction peaks.When  any gaseous or solvent species are adsorbed on the crystal surface, the species are distributed at random and no periodicity would occur  within the adsorbed species to generate a new lattice at lower concentration of the adsorbed species.At higher concentration this may result in the formation of a solvate and this should result in the formation of a new lattice yielding additional peaks.However, if these species enter the bulk of the crystal lattice , it may result in the change in the unit cell dimensions of the original crystal  and subsequently bring about the change in the unit cell volume of the crystal

  • Xueqian Zhang asked a question:
    How could I 'cut ' a small piece of ceramic for TEM or XRD?

    As the title.

    I need a small piece of ceramic like 0.1mm or smaller cut from a for TEM, maybe some other for XRD.

    how can I do that?  I am doing some search. But in the same time, please....

    thank u guys .

  • Emmanuel Garnier added an answer:
    Any advice on Quartz XRD plate analysis?


    I just ordered XRD plate ( Quartz plate).

    when I run the plate without sample I got the results on the picture is this results normal ?

    and How can I calpreat the plate to get good result?

    any suggestion  what to do?

    thanks alot

    Emmanuel Garnier

    check "zero background holder" google or in "journal of applied crystallography"

  • Ravi Ananth added an answer:
    In XRD analysis ,can Fullprof calculate crystallite size when you doing rietveld refinement?

    I am using new version of mach (version 2.3.3), and this software use fullprof in the background for rietveld refinement and give you the result, like quantitative analysis. but there is no sign crystallite size in the report.

    When the refinement was completed, the match gives you Fullprof refined files, I want to know If I can use these files and refine crystallite size with Fullprof myself?

    Ravi Ananth

    Similar recommendation as Daniel Wildson's!

    Translated by Google for the rest of us :-)

    "Hello Gianfranco, you can not calculate the contribution size and / or strain if you do not know the instrumental contribution. fullprof with you
    1) determine the contribution instrumental with a standard sample doing a normal raffinament, but using the function NPR = 7;
    2) use the parameters obtained to make your file IRF (just take one of the examples of the IRF file and we replace your values)
    3) make the refinement of your stage ustlizzando your file IRF and the function NPR = 7; if you make the refinement of the parameters of strai / size anisotropic, you have to impose the correct model (strain model or size model) depending on the space group phase you are studying. the results will find them in the file that you MIC is generated at the end of the fit"

    Note: Do remember that the effect of the  shape of the coherent diffracting domains cannot be resolved with this method using conventional equatorial scan diffractograms only (nor can any existence of "preferred orientation")! It must be assumed in the "model". Unless one has corroborating SEM or TEM data the assumption may result in errors. It is easier to use this method to examine samples relative to "known standards" :-)

  • Sami Mahmood added an answer:
    Can someone give advice about XRD rocking-curve issue?

    When I measure rocking-curve of (111) reflection of 100nm-thick Pt thin films deposited at high temperature on Si-SiO2 substrates, the rocking-curve has its classical shape with a FWHM of about 1-1.5° (Figure 1).

    Due to technical problem, I had to change the way to deposit Pt films and I have now to deposit at room temperature and anneal under air in a conventional furnace. The shape of the rocking-curve is completely different (Figure 2).

    As I have never seen this before, can someone try to explain me?

    Thank you

    + 1 more attachment

    Sami Mahmood

    I have noticed a noticeable shift in the peak positions of the two samples. Such shift could arise from lattice strain, and could be responsible for the observed asymmetry in the room-temperature deposited film. This seems to support the viewpoint of Mark Rikel regarding the stress in the sample. Also, the relative orientation of the film surface with respect to the substrate and zero beam direction would obviously result in the observed asymmetry as Ulrich Krebs suggested. 

  • Abdelali Hallaoui added an answer:
    How can I explain the difference of peak intensities for the same material on XRD?

    There are 2 XRD data with different intensity came from the same material (SrFe12O19).

    To be more clear, in first one, the intensity of (107) peak is stronger than (114) peak. However, in the second one, that of (114) peak is dominant. How can I explain the difference of peak intensities for same material?

  • Nasirudeen Olalekan Ogunlakin added an answer:
    How can I convert an XRD JADE (*.pid or *.raw) file into a file supported by X'Pert HighScore Plus?
    I have data obtained by rigaku rint XRD through JADE software. My data is in *.pid and *.raw format but unfortunately X'Pert HighScore Plus is not supporting both file format, so i I want to change file format of diffraction data. I have used MATCH software, but it done not helped.
    Nasirudeen Olalekan Ogunlakin

    PowDLL works fine on windows 10 for me. Its an excellent software

  • Jyoti Jaiswal added an answer:
    How can I calculate gap between grain size in thin film?

    I have XRD pattern of thin film. I have calculated structural properties from the XRD spectra. I have also SEM micrograph of these film. The shape of grain size is hexagonal. Now, I want to calculate the gap between the garin size. Please guide me. Thanks.

    Jyoti Jaiswal

    Thank you so much to Thomas Walther and L. Slewa for guide me.

  • Bhavya G. added an answer:
    Is it possible to know the compound by powder XRD pattern analysis?

    The pure precipitated unknown compound obtained as  the result of bacterial cellular mechanism was subjected to XRD study, result's is indicating the crystalline nature. here we are intrested to known its chemical composition.

    1. Is it possible to known?

    2. Is there is any software, which is user friendly for analysis....?

    3. what are other techiques we can approch for ?

    Thank you 

    Bhavya G.

    Thank you for your valuable  suggestion... 

  • P. Grima Gallardo added an answer:
    If I need to calculate the crystallite size with the Scherrer Equation, how can I choose its peak?

    1) If I need to calculate the crystallite size with the Scherrer Equation, how can I choose its peak? 

    2) In the Scherrer Equation d = (k * lamda) / (FWHM * cos (2theta) ), the FWHM value is Full Width at Half Maximum, but in the Excel spreadsheet containing the Scherrer's Equation (see the attachment), they calculate d by replacing FWHM with [ FWHM (structural) = FWHM (observed ) - FWHM (standard) ].

    Could someone please explain this replacement? I also don't know how to find the ref value needed for FWHM (standard).

    Thanks in advance!

    P. Grima Gallardo

    I agree with the excellent previous given answers, however I want to express my opinion. The FWHM of the diffraction peaks is the convolution of the detector and sample response, given by equation:


    where (FWHM)obs are the observed values, (FWHM)elect is the noise term which comes mainly from the amplification system and (2.35^2 Fe) comes from the hole creation statistics. F is the Fano factor (near to 0.1 for Ge detectors at 77K), e is a term which relates the energy to the number of free carriers created in the process and has a value of 2.9 eV for Ge detectors and E is the energy in keV.

  • Ravi Ananth added an answer:
    When using the Debye-Scherrer equation for calculating particle size (D=Kλ/(β cos θ) does one have to halve the FWHM(β)? Must all angles be in Radians?
    The Debye-Scherrer method is used to obtain X-ray diffraction measurements in powders.This method is applicable to crystallites ranging from 1.0 to 0.01 μm in diameter, but the grains must have good crystallinity.
    Ravi Ananth
    • "The functional from of the two equations is the same". Thanks Matt!
    • "FWHM of the peak measured in 2theta", because most diffractograms are coupled Omega-2Theta scans.
    • Is it possible to apply this formula for various (hkl)'s at multiple θ's  and get a feel for the shape of the "particle"?
  • Alberto Martinelli added an answer:
    How can one estimate the type of an unknown atom by refining the occupancy of that atom during the Rietveld structure refinement?

    If the original unit cell (containing A,B and C atoms) is doped with D and E atoms for example, and we have found some possible atomic sites for an unknown atom, how is tit possible to understand the type of the unknown atom (whether it is D dopant or E dopant or even non of them) by refining its occupancy?

    Alberto Martinelli

    if you have a synthetic pure compound you know the exact amount of the different atomic species, so it is quite easy to check what is the best structural model. in addition you stated that E is a light element, whereas D seems the heaviest one in your phase; so it is highly unikely that they both occupy the same site. for example you guess that D substitutes A: then you can prepare a structural model accordingly (that is with the nominal content of A and D at the same atomic site) and see if the refinement improves (peak fit, R-factors) to confirm.

  • Ravi Ananth added an answer:
    XRD: can I quantify the ratio of two components in a sample from the intensities of the XRD reflexes?

    I have a sample consisting of Ir and IrO2. The XRD-pattern shows the reflexes of both components with similar intensities of the respective main peaks. Peaks are of comparable width.

    Do I have a chance to roughly quantify from the peak intensity ratio, the molar ratio of these two components in the sample?

    Ravi Ananth

    How do they account for the effect of "preferred orientation" and variations of the "Relative Intensity Ratio" as a result of particle size/strain/shape etc.?

  • Ravi Ananth added an answer:
    How can i measure relative crystallinity % for x-ray diffraction?
    Relative crystallinity was defined as the ratio of the peak area to the total area of a diffractogram (which is the sum of peak areas and amorphous areas) expressed as a percent By using origin pro how can i measure area under crystalline peaks and compared to total areas?
    Ravi Ananth

     Good reference Wissam! Thanks!

    All they need to do now is to extend the analyses from the conventional 1D equatorial diffractogram to a 2D diffractogram invariably involving some extent of "preferred orientation" convoluted in the XRD signal. Calibration with "known standards" would help "relative % crystallinity" detection. Consistent sample prep would be key in any such endeavor along with WPPM concepts to deconvolute individual constituent XRD signal :-)

    See example of Kevlar & Aluminum below. I'd be interested in such publications of similar analyses with 2D diffractograms if and when you have any.

  • Thang Quang Do added an answer:
    Can anybody help me to solve the powder XRD of MNPs which were synthesized by hydrothermal method? (attached XRD spectra)

    I have prepared MNPs (expected CuFe2O4) from aq. solutions of FeCl3 (1 eq) and CuCl2 (0.5 eq), urea (10 eq), glucose (10 mol%), and 30% aq NH3 (10 mL), ethgylene glycol (10 mL) by hydrothermal  method at 180 oC, for 8h. There are two possibilities to form either carbon coated CuFe2O4 or CuO/Carbon/Fe3O4 NPs.

    The mechanism for formation of CuO/Carbon/Fe3O4 might be as follows: The glucose can reduce Fe(III) to Fe(II) to form carbon coated Fe3O4 followed by stabilization of insitue generated CuO from CuCl2 in presence of basic medium (aq. NH3).

    or Carbon coated CuFe2O4 can form from the reaction among FeCl3, CuCl2, glucose in presence of basic medium.

    Please help me to solve PXRD (attached) of this material.

    Thanks in advance

    Thang Quang Do

    This is the pattern of Fe2O3.

  • A. Márquez-Herrera added an answer:
    Why is there no peak for XRD analysis for CuGaO2 transparent thin film even after annealing?

    Im using RF sputtering deposition technique.The maximum temperature that i used for annealing is 500C, because temp more than that will affect the glass slide that i used as a substrate. The XRD pattern only show the amorphous pattern of the glass slide. Can someone please give me a reasons why? thank you

    + 1 more attachment

    A. Márquez-Herrera

    I suggest to change the glass to quartz due Quartz materials is more transparent than glass in UV-Vis experiments (less 200 nm). Also you can use a higher temperature in quartz (about 1300° C). Finally, try to perform the DRX experiment in grazing incident angle.

  • Tomasz Jaroń added an answer:
    Why Cu Kalpha1 to Kalpha2 intensity ratio can be different than ca. 2:1?

    I have a problem with refinement of a powder pattern in which Kalpha1 and Kalpha2 peaks are quite well separated at higher angles (low FWHM). What is weird, the ratio of Kalpha1 to Kalpha2 peaks is ca. 3:1 (as judged by eye - see the attached picture). The refined intensity ratio (in GSAS2) is 3.045.

    Does anybody know why the intensity ratio is different that ca. 2:1?

    Also, the Kalpha2 peaks are slightly shifted. I have no idea how to refine this pattern (I am rather experienced here - have solved and refined dozens of structures...).

    Tomasz Jaroń

    Dear Ravi,

    Now the ratio of Kalpha and Kalpha2 peaks is visually around 2:1, and Rietveld refinement is possible.

  • Clifford Chafin added an answer:
    The band Gap happens because the diffraction "touch" in the Brillouin Zone?


    I'm study about band structure... and I read this:

    "We have noted that diffraction occurs when one end of a wave vector touches a Bragg plane. In the context of nearly free electrons, diffraction causes the E Vs k relationship to distort in the vicinity of the Bragg planes (or Brillouin zone boundaries). This distortion causes some of the energy levels to become forbidden to the nearly free electrons, which results in the presence of band gaps in the material."

    link: http://nptel.ac.in/courses/113106040/Lecture32.pdf

    And I read in different places.. but still don't understand why happen this gap because the diffraction.


    Clifford Chafin

    I have always hated these sorts of explanations and I understand why you find it confusing.  The actual band gaps are not well approximated by nearly free electron theory but by Green's function methods.  This implies the right way to think about what is going on here is that the states near the BZ are mixing more strongly in a correlated way so that there is a split.  What does this have to do with Bragg diffraction?  The edges of the zones are where Bragg diffraction occurs.  Does this mean that this diffraction "causes" the splitting?  I find this suggestion kind of a stretch.  What matters is that this is exactly where the interactions of the states is the largest so they can mix.
    The usual nearly free electron model makes more sense for neutral fermions in periodic optical potentials for ultracold gases.  At least here the necessity of treating electrons near the fermi surface as weakly interacting quasiparticles is not necessary.  Interestingly, we usually apply the nearly free electron theory to explain gaps that are not so near the fermi surface anyway where we don't expect the quasiparticle assumption to be valid. 

    Maybe you will like the optical analog better.  When light passes through a dielectric what "causes" the band gaps to open up?  One can view the diverging internal energy storage of the the electromagnetic wave near resonance as the driver of such forbidden frequencies in the spectrum.  Such frequencies can only generate evanescent waves.  I made a pretty picture of this in the paper below.  

  • Roman Nikolaevich Vasin added an answer:
    How can I find out the purity and particle size quantitatively from PXRD data?

    From the sharpness of peak we conclude whether it is amorphous or crystalline and from the appearance of extra peaks impurities are suggested. But these suggestions are qualitative. Could we establish a numerical value for the purity and particle size?

    Roman Nikolaevich Vasin

    There were some discussions on this matter already. Please, use the 'Search' functionality. E.g. https://www.researchgate.net/post/How_can_I_get_the_percent_of_crystallinity_from_Powder_XRD_data/1



    And a general advice - do not use Scherrer's equation, in 99% of cases it will provide you with meaningless results.

  • Igor P. Zibrov added an answer:
    Is it possible to find new crystal's cell parameters using powder XRD results?

    Is it possible to find new crystal's cell parameters using powder XRD results?

    Igor P. Zibrov

    It is not big problem if the symmetry is high (cubic, hex., tetrag., ortho), but if the symmetry is monoclinic or triclinic you need to remember two rules: 1-XRD data must be of a high quality (use only K alpha 1 irradiation); 2-you must be sure that your powder is a single phase. TREOR is an indexing program in EXPO, you can try it.

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