Bragg x-ray scattering in KBr

exercise 3_4941

The results of x -ray scattering data from a polycrystalline KBr powder sample are shown in the figure.

(a) What are the wavelength and energy of the x -ray radiation?

(b) Suppose that there were no labels on the peaks in this figure. How could one determine just from the angular values of the peaks that the crystal has a lattice that is fcc and not bcc ?

KBr has the same crystal structure as NaCl with a lattice constant of a = 6.59 Å .