How to calculate lattice parameters?

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    Lattice Parameters
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Discussion Overview

The discussion revolves around the methods for calculating lattice parameters of alloys, specifically focusing on the role of X-ray diffraction (XRD) and the use of experimental data from databases. Participants explore how these parameters are derived and the processes involved in obtaining them.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants suggest that lattice parameters are usually obtained through XRD, while others mention that calculations are possible for simple alloys.
  • There is a discussion about whether the values found in tables are primarily experimental data, with some participants confirming that they are derived from experimental work and databases like JCPDS cards.
  • One participant notes that complete molecular structures can be obtained from crystal XRD if the sample is crystalline, although the time required for experiments is uncertain.
  • Another participant mentions the use of inverse lattice methods to find axis values by comparing experimental images.
  • Some posts include mathematical expressions, though their relevance to the discussion is unclear.

Areas of Agreement / Disagreement

Participants generally agree that XRD is a primary method for obtaining lattice parameters, but there is no consensus on the specifics of the calculation methods or the time required for experiments. Multiple viewpoints on the derivation of data from experimental sources and databases remain present.

Contextual Notes

Some assumptions about the availability of experimental data and the conditions under which XRD can be performed are not fully explored. The discussion does not resolve the complexities of calculating lattice parameters or the specifics of the experimental processes involved.

Who May Find This Useful

This discussion may be useful for researchers and students interested in materials science, crystallography, and the methods used to derive structural parameters of alloys.

nakamura25
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Dear Friends,

I read some articles about alloys. Most articles have a table listing lattice parameters (a,b,c-axis) and unit cell volumes. But they never explain how those data come from.

How do we get those data? By comparing XRD images with PDF databases? Or by calculation?

Example:
La(Ni3.8)Al(Mn0.2)
a = 5.0902 angstrom
b = 4.0812 angstrom
c = 0.8018 angstrom
v = 91.5765 cubic angstrom

Thank you in advance for your kindly answer!
 
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Usually via XRD.
It IS possible to calculate lattice parameters of some simple alloys, but values you find in tables are (nearly) always experimental data.
 
f95toli said:
Usually via XRD.
It IS possible to calculate lattice parameters of some simple alloys, but values you find in tables are (nearly) always experimental data.

Thank you for answering!
Experimental Data?
Do you mean someone did experimental works and made them into databases (like jcpds cards)? And the article writers just quoted those data and made a table of it.
 
Hi,
yes someone, technician, or a person who know how to work with a XRD...
The complete molecular structure can be obtained from crystal XRD provided your sample is crystalline (i exactly don't know how long will it take to make one experiment). By this method you get complete data, almost everything about the structure in internal coordinates and so on..
 
Rajini said:
Hi,
yes someone, technician, or a person who know how to work with a XRD...
The complete molecular structure can be obtained from crystal XRD provided your sample is crystalline (i exactly don't know how long will it take to make one experiment). By this method you get complete data, almost everything about the structure in internal coordinates and so on..

Thanks! Now I understand how it is done.
Happy New Year!
 
<br /> <br /> {\cal L}_R = \sum_{i=1}^G<br /> \bar{E}^i_R(i\kern+0.1em /\kern-0.55em \partial<br /> - g_1Y_E \kern+0.1em /\kern-0.65em B)E^i_R +<br /> \bar{D}^i_R(i\kern+0.1em /\kern-0.65em D<br /> - g_1Y_D \kern+0.1em /\kern-0.65em B)D^i_R +<br /> \bar{U}^i_R(i\kern+0.15em /\kern-0.65em D<br /> - g_1Y_U \kern+0.1em /\kern-0.65em B)U^i_R<br /> <br />
 
Cool.
 
That was mine said:
<br /> <br /> {\cal L}_R = \sum_{i=1}^G<br /> \bar{E}^i_R(i\kern+0.1em /\kern-0.55em \partial<br /> - g_1Y_E \kern+0.1em /\kern-0.65em B)E^i_R +<br /> \bar{D}^i_R(i\kern+0.1em /\kern-0.65em D<br /> - g_1Y_D \kern+0.1em /\kern-0.65em B)D^i_R +<br /> \bar{U}^i_R(i\kern+0.15em /\kern-0.65em D<br /> - g_1Y_U \kern+0.1em /\kern-0.65em B)U^i_R<br /> <br />

Do you have a website defining those parameters?
Thanks!
 
Hi,
In our univesity we have X-Ray laboratory.They do such these things.By using inverse lattice and compering with experimental images you can find axis valuse.
 

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