CHY 102 Lecture Notes - Lecture 42: Cubic Crystal System, Close-Packing Of Equal Spheres, Atomic Radius
Document Summary
Repeating 3-d pattern of points in space. One basis unit at each lattice point. Lattice comprised of repeating units called unit cells. 1 atom per cell: (4/3) r3/(8r3) = /6 = 52. 4% 2 atoms per cell: 2 (4/3) r3/(r3(16/3)3/2) = 68. 0% Packing the most amount of stuff into the smallest amount of space/time! Close packing maximizes atomic interactions and minimizes the volume. Vanadium (v) crystallises in a bcc structure and has an atomic radius of 131 pm. Determine the density if the edge length of the bcc unit cell is 4r/ 3 and the atomic mass is 50. 94 g/mol. (na = 6. 022 1023 mol: 3. 06 g/cm3, 6. 11 g/cm3, 2. 77 g/cm3, 12. 2 g/cm3. 2 atoms/cell: 2/(6. 022 1023 mol-1) = 3. 321 10-24 mol. Solids and liquids classified by forces of attraction. Properties of substance result from forces of attraction. Phase change data summarised by heating curves & phase diagrams. Crystal structure of solids classified by crystal lattice and the basis.
