Dear Amaranath,

XRD analysis is a comprehensive topic and do require some expertise when it comes to analyse the XRD data.

Basically when you do XRD on any material, it provides you with a range of peaks (for crystalline materials) and humps sometimes (for amorphous material). Theoretically every single material has unique XRD peaks (finger prints). There are different databases (JCPDS,  ICDD, COD etc.) that have XRD patterns of all known materials. So in simple term, you match XRD pattern of your material with its corresponding material using automatic function on various available XRD data analysis software. However, it gets complicated when you have a mixture of different phases/ materials and that would require a lot of work and analysis by other complementary techniques.

I suggest you to start from reading any basic book on XRD analysis and then get some hands on experience with some expert in your institution.

Wish you all the best.

Rehan

Dear Amaranath,

XRD analysis is a comprehensive topic and do require some expertise when it comes to analyse the XRD data.

Basically when you do XRD on any material, it provides you with a range of peaks (for crystalline materials) and humps sometimes (for amorphous material). Theoretically every single material has unique XRD peaks (finger prints). There are different databases (JCPDS,  ICDD, COD etc.) that have XRD patterns of all known materials. So in simple term, you match XRD pattern of your material with its corresponding material using automatic function on various available XRD data analysis software. However, it gets complicated when you have a mixture of different phases/ materials and that would require a lot of work and analysis by other complementary techniques.

I suggest you to start from reading any basic book on XRD analysis and then get some hands on experience with some expert in your institution.

Wish you all the best.

Rehan

Dear colleague Amaranath Govindolla,

Have a nice time and good day.

Your question "How to determine the structure of a specimen from XRD?" is interesting, it can be consider as a student course in the first degree of the university. Our colleague Dr. Mohammad Rehan gives you how to start and following such this issue?. The following paragraph may help you too.

The materials (solid, liquid or gas) may have at least one phase of the next phases:

1-  Amorphous: the material has no order or specified structure, it also may be called short range order, SRO. Such this phase of material is characterized by broaden hump through the XRD within the low range of  the angle (theta) and no sharp diffraction peaks could be identified, see the two figures titled (attached) as XRD of amorphous and the other one titled XRD of amorphous- crystalline. Also the low intensity could be used as indicator for small particle size.

2-  Poly crystalline materials: the material may has some extent of order, specified structure and phases may be identified. It also may be called medium range order, MRO. May be few or many sharp diffraction peaks with preferred orientations could be identified. Bragg low can be used to lattice spacing and also lattice parameters (a,b,c) could be determined. The crystallite size of the produced phase could be calculated using The well known Sherrer equation [J.K. Williamson, W. Hall, Acta metallurgica, 22 (1853) 1, M. M. El-Nahass, H. S. Soliman, A. El-Denglawey, Appl. Phys. A 122 (2016) 775]. The intensity of XRD in such case has higher values than the case of amorphous material.

3-  Single crystal materials; the XRD of these materials has sharp diffraction peaks with preferred orientations and with high intensity and low full width half maximum, FWHM. Such these materials called long range order, LRO. All parameters of crystal structure; lattice parameters, miller indices, particle size and micro-strain (in case of the presence of peak's shift) can be determined.

I wish this is useful and help you.

Yours

A. El-Denglawey

Dear colleague Amaranath Govindolla,

Have a nice time and good day. 

The attached file "How to Analyze Polymers-XRD" teach you easilly how to indentify the XRD and any material. If you read the mentioned attached file carefully with deep inderstanding you will be an expert in XRD analysis.

I wish this is useful and help you.

Yours

A. El-Denglawey

For crystalline materials, it is possible to calculate all the diffraction pattern for certain atomic structure. There are multiple factors involved for XRD peak positions and intensities. The structure factor is most important, which determines crystal plane to have either constructive or destructive interference. It depends on the crystal structure (unit cell), position of atoms in the unit cell, and also the atoms at the position. Thus, you can simulate the expected XRD patterns with corresponding planes if you know the crystal structure. Of course you can do experimental XRD for actual sample, and back calculate for the detail of the crystal structure. Different crystal structure result a different patterns that is related to unique order of h^2+k^2+n^2. You may easily find the description for it from any XRD textbooks.

For calcite, depends on the metal, the crystal structure can be different. CaCO3 is trigonal while Na2CO3 can be either Monoclinic or Orthorhombic. Thus the expected XRD peak is different. Also at the peak center for a specific plane, the lattice constant can be calculated. The FWHM can be used for the average domain size analysis when the equipment induced errors are well determined.

Good morning:

Since my experience, you can use a comparison method. If you have a theoretical XRD and empirical data of any perovskite sample, you can use XRD software, for example, Powder Cell for Windows (PCW) and SPuDS. Actually in my thesis, I use this software for a really good comparison method; this results will be used to apply Rietveld refinement method. For more questions, please contact me. Regards.

Dear Amaranath Govindolla,

by measuring the reciprocal lattice space (k-Space) by XRD diffraction technique if you take Fourier transform of that it will give you bravais lattice. this bravais lattice will give you the information about crystal structure. 

There are many software used to analyze the XRD-patterns and conclude the crystal structure and its symmetry, one of the best software is Highscore, Match and Diamond. if you have a problem i can help you

I agree with Emad that Highscore is one of the best and more comprehensive software to analyse XRD data than many other available software.

Compare with the JCPDS data

Yes, Xpert Highscore is a very good complement to SPuDS and PCW. They allows a convenient manipulation of lattice parameters and GII values for a crystallographic structure...

Dear Dr. Amaranath Govindolla

Have an nice time

I concur with Dr. Emad Alshakarchi and Dr. Mohammad Rehan.

The crystal structure of any sample can be identified by using two methods: computationally and Manually.

Computationally, there are many software can be used to analyze X-Ray diffratograms and deduce the crystal structure of investigated sample. For example, you can use Highscore software, which is one of the best software in this regard.

Yes, as mentioned Dr. Rehan, this software is more comprehensive than many other software programs to analyse obtained XRD data.

Manually, You can compare you XRD patterns with JCPDS (or PDF) cards, but here you must know the elements which consist of your invigtigated sample.

Good luck

Dear  Amaranath 

You can determine the structure  of a polycrystalline specimen / a single crystal specimen by the X-ray diffraction (XRD) structure analysis by simply

applying Bragg's law;

2d Sin(Theta)=n (Lambda, the wavelength of the incident wave)

where;

d is a structure parameter which uniquely distinguishes each polycrystalline/single crystal element in term of a unit lattice "a" of a specific h, k, l Miller indices of Bragg plane;

d=a/([h2+k2+l2])0.5     

Theta is the diffraction angle of the incident wave.

n is a positive integer.

Lambda is the wavelength of the incident wave.

So, when an incident wave (x-Ray) of a known Lambda was scanned  over a range of angle value, Theta range, on a polycrystalline/a single crystal sample and diffraction occurs at a specific Theta, one can determine the structure parameter (d) of the specimen. by using Bragg's law's from the  known values of Lambda and the diffracted  Theta.   As a result, the unit lattice "a" of the element of the specimen can be determined from the a=d([h2+k2+l2])0.5  as well.  

You have the intensity peaks and the diffraction angles. Let's say you suspect the material is cubic, how do I find if it's simple cubic or BCC or FCC?

You are measuring the k-space (reciprocal lattice space) points with the x-ray diffraction. The Fourier transform of these points (provided you measured enough of them) gives you exactly the Bravais lattice.

The Bravais lattice is the crystal stucture! You then have to look at the Bravais lattice and construct a Wigner-Seitz unit cell, then that construction will determine your crystal type

How can X-ray diffraction be used to determine the crystal structure? - ResearchGate. Available from: https://www.researchgate.net/post/How_can_X-ray_diffraction_be_used_to_determine_the_crystal_structure [accessed Nov 25, 2016].

Dear Amaranath, you can easily get the reference card (JCPDS) of calcite and can match it with your original XRD data. Maximum three high intense peak you would have to match with corrosponding 2 theta angle, and then you can identify your phases as well material.

its Very simple. you just need to know about the lattice parameter "a" of your material. if you have it then you can use the well known formula 

d =     a/(h2+k2+l2)1/2

And thus if a is known you can arrange it as.

(h2+k2+l2)1/2   = a/d

While d is given in XRD which is different for each set of 2 theta.

Now use hit and trial method by assigning such values to h,k&l  that you answer matches your lattice parameter “a” that you already know. So if the h, k and l  all are either odd or even so your structure is Fcc other wise if h+k+l =even so structure is BCC 

Aqib, and if 'a' is not known, what then? This is fine for cubic structures only but Amaranth asked about calcite...

Dear Aqib

I have the same reservation as Mr. Ian pointed out,please clarify?

ok i admit that i was mistaken.thanks to Mr. Ian and Mr. Naveed

 Dear Naveed Akhtar and Mr. Ian!

Can you do me a favor?

How to make 0.4M solution of bismuth oxide and Nitric acid. and 0.4M solution of Fe(NO3)3.9H2O in De Ionized water.?? Edit

Formula unit of HNO3 is 63g and that of Bi2O3 is 465.96g

and Fe(NO3)3.9H2O is 404g

How to make 0.4M solution of bismuth oxide and Nitric acid. and 0.4M solution of Fe(NO3)3.9H2O in De Ionized water.?? - ResearchGate. Available from: https://www.researchgate.net/post/how_to_make_04M_solution_of_bismuth_oxide_and_Nitric_acid_and_04M_solution_of_FeNO339H2O_in_De_Ionized_water [accessed Dec 5, 2016].

Aquib, I suggest that you post this as a separate question for maximum exposure. It is buried here in the wrong topic. Best you delete from this thread.