Key points in crystallography Miller indices,Bravis-Miller indices for hexagonal structure Lattice spacing calculation Reciprocal lattice <-real lattice Know how to read a crystal structure Table 1.4 Crystallographic data for FeC,iron carbide or cementite,which exists in equilibrium with a-Fe in most steels Pearson Structure symbol a,b,c x,B,7 Point Phase type space group (nm) ) Atoms set X Occ CFe3 CFe3 oP16 Pnma 0.50890 C 4c 890250450 100 0.67433 Fe1 4c 036250852 100 0.45235 Fe2 8d 186063328100Key points in crystallography • Miller indices, Bravis-Miller indices for hexagonal structure • Lattice spacing calculation • Reciprocal lattice <-> real lattice • Know how to read a crystal structure