Question

In: Physics

Using powder X-ray diffraction to analyse a metal compound, a simple pattern of peaks resulted, where...

Using powder X-ray diffraction to analyse a metal compound, a simple pattern of peaks resulted, where the largest peak existed at an angle of 2θ= 19.8°. However, when a similar sample was analysed that contained a metallic impurity, this 2θ value became 22.4°. What does this suggest is happening to the crystal lattice and why?

Solutions

Expert Solution

According to Bragg diffraction condition () we know that diffraction angle and inter-planer spacing are inversely related with each other

                                                      .

Therefore in the preset case, the increase in diffraction angle from to is associated with the decrease in the inter-planer spacing d. Therefore, with the incorporation of metallic impurity in the sample, d value decreases. The decrease in d value is associated with the compressive strain in the lattice. In other words, metallic impurities distort the original crystal structure of the lattice by varying bond lengths, bond angles etc. and hence, changes the lattice parameter. Such distortion arises due to the random incorporation of the metallic impurities in the lattice.


Related Solutions

The first four peaks in the X-ray powder diffraction pattern of sodalite are at 2 values...
The first four peaks in the X-ray powder diffraction pattern of sodalite are at 2 values of 9.97°, 14.12°, 17.32° and 20.02°. The radiation used for the experiment was Cu K with  = 1.5418 Å. Determine the lattice type and calculate the length, a, of the cubic unit-cell.
what are two experimental considerations when running PXRD (powder X-ray diffraction) using a flat disk sample...
what are two experimental considerations when running PXRD (powder X-ray diffraction) using a flat disk sample holder? And why is the scan time and 2theta range important parameters in the experiment?
Describe the powder X-ray diffraction experiment. List the basic components in your diagram and discuss the...
Describe the powder X-ray diffraction experiment. List the basic components in your diagram and discuss the features/roles of each component. Include Bragg’s Law as well as coherent and incoherent scattering. What types of information can be obtained using this technique? Pros and cons with respect to single crystal XRD?
Assume that an X-ray diffraction pattern is taken from two specimens of pure Ni. The two...
Assume that an X-ray diffraction pattern is taken from two specimens of pure Ni. The two specimens are identical except that one contains numerous twins, while the other is untwinned. Would the XRD patterns show a larger number of diffraction peaks for the specimen containing the twins? Explain the reasoning behind your answer.
what is the difference between x-ray imaging and the x-ray diffraction?
what is the difference between x-ray imaging and the x-ray diffraction?
a) you observe that an X-ray diffraction pattern has a strong peak at 2 theta=100.7 degrees....
a) you observe that an X-ray diffraction pattern has a strong peak at 2 theta=100.7 degrees. using the following facts, calculate the d spacing for this peak (given-wevelenght xray=0.154nm,sin100.7=0.98,sin50.35=0.77 b) How many atoms are in a Hypothetical diamond cubic structure with double the number of internal atoms and superimposed body centered cubic atom c) Calculate the packing factor for face centered cubic crystal that has a centeral impurity atom that fills the interstitial space
Do you expect to get a different x-ray diffraction pattern for two samples of pure Aluminum:...
Do you expect to get a different x-ray diffraction pattern for two samples of pure Aluminum: Sample #1 – a cube 1cm x 1cm x 1cm in size, or Sample #2 - a powder of aluminum with a particle size diameter of 1 mm?
X-Ray Diffraction Explain the different geometries (2) of a diffractometer? Where is the sample, source, and...
X-Ray Diffraction Explain the different geometries (2) of a diffractometer? Where is the sample, source, and detector?
1. Derive the Braggs law of x-ray diffraction ?
1. Derive the Braggs law of x-ray diffraction ?
Powder diffraction for a pure metal yields the following dhkl spacings values (nm): 0.2088, 0.1808, 0.1278,...
Powder diffraction for a pure metal yields the following dhkl spacings values (nm): 0.2088, 0.1808, 0.1278, 0.1090, 0.1044, 0.09038, 0.08293, and 0.08083. A monochromatic x-radiation having a wavelength of 0.1542 nm was used. Use this information to find the following: a) Is the pure metal FCC or BCC? b) Determine the lattice parameter. (c) Determine the atomic radius and the metal using the values listed in Table 3.1 (or from the list in the front cover of Callister)
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT