1.A powder diffraction pattern is recorded on a sample of an unknown elemental substance known to...
1.A powder diffraction pattern is recorded on a sample of an unknown elemental substance known to have cubic symmetry. Cu K-alpha x-rays (wavelength of 0.154 nm) are used and the 0 values of the first 7 peaks are 14.22, 23.64°, 28.05°, 34.550, 38.17°, 43.99° and 47.45° (a) What are the lengths of the reciprocal lattice vectors (or change in x-ray wave-vector) corresponding to these Bragg angles? (b) For a cubic structure, these lengths should be equal to (2r1/a)(h+k+P)2, although depending on the structure factor some hkl combinations may be missing. Try squaring the lengths and find a common divisor, which converts the G2 values into approximate integers. Which h,k,l combinations give (h2+k2+P) that match this set?