Q4(a). Powder XRD: lattice type, cell edge and density
(i) Powder XRD of a crystalline material exhibited diffractions at 2θ values corresponding to the following planes: (110), (200), (211) and (220). The material belongs to which crystal structure? Give reasons. (ii) Determine the density of the material. Given: sin 30° = 0.5, sin 60° = √3/2; Molecular mass of the material = 60 g/mol; (211) plane is observed at 2θ = 60 degree; λ = 1.54 Å.
Answer in brief
Body-centred cubic (bcc): every reflection has h + k + l even; d₂₁₁ = 1.54 Å, a = 3.77 Å, Z = 2, so ρ = 3.71 g cm⁻³.
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Coverspowder XRDBragg's lawbody-centred cubicsystematic absencesdensity from unit cellMiller indices
All parts of Question 4
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