The five Bravais lattices in 2-D are: oblique (monoclinic), rectangular (orthorhombic), cantered rectangular (orthorhombic), hexagonal, square (tetragonal) A cube has nine plane of symmetry. Three of the planes run parallel to the faces of the cube, and the other six run diagonally from one edge to the opposite edge. For monoclinic system, a≠b≠c and α=γ=90∘,β≠120∘ The packing fraction of BCC is 68%