Solid State: The 15 Things You Cannot Afford to Forget

1. SC: Z=1, CN=6, PE=52.4%, a=2r
2. BCC: Z=2, CN=8, PE=68%, a√3=4r
3. FCC: Z=4, CN=12, PE=74%, a√2=4r
4. HCP: Z=6 (full cell), CN=12, PE=74%, c/a=1.633
5. Density: ρ = ZM/($a^{3}$Nₐ); 1 Å = 10^{-8} cm; 1 pm = 10^{-10} cm
6. n close-packed atoms → n oct voids + 2n tet voids
7. Tet void radius ratio = 0.225; Oct = 0.414
8. NaCl: $Na^{+}$ fills ALL octahedral voids (4), CN=6:6
9. ZnS: $Zn^{2+}$ fills HALF tetrahedral voids (4 of 8), CN=4:4
10. CsCl: CN=8:8; $CaF_{2}$: CN=8:4; $Na_{2}O$: CN=4:8
11. Schottky: density decreases; Frenkel: density unchanged
12. AgBr: shows BOTH Schottky AND Frenkel — exam favourite
13. F-centres: n-type; metal deficiency: p-type
14. Group 15 dopant → n-type; Group 13 → p-type
15. Fe, Co, Ni = ferromagnetic; MnO = antiferromagnetic; $Fe_{3}O_{4}$ = ferrimagnetic