2. Crystal Structure

crystal systemonly 7 different types of unit cells14 standard (Bravais) unit cells coulddescribe all possible lattice networkscrystalsystemaxial lengths &interaxial angles space latticecubic a = b = c simple cubicα = β = γ = 90 o body-centered cubicface-centered cubictetragonal a = b≠ c simple tetragonalα = β = γ = 90 o body-centered tetragonalorthorhombic a ≠ b ≠ c simple orthorhombicα = β = γ = 90 o body-centered orthorhombicbase-centered orthorhombicface-centered orthorhombicrhombohedral a = b = c simple rhombohedralα = β = γ ≠ 90 ohexagonal a = b ≠ c simple hexagonalα = β = 90 oγ = 120 omonoclinic a ≠ b ≠ c simple monoclinicα = γ = 90 o ≠ β base-centered monoclinictriclinic a ≠ b ≠ c simple triclinicα ≠ β ≠ γ ≠ 90 o2