GEOL 2500 Lecture Notes - Lecture 1: Orthorhombic Crystal System, Miller Index, Atomic Packing Factor

• School: University of Manitoba
• Department: Geological Sciences
• Course: GEOL 2500
• Professor: Chakhmouradian Anton

Document Summary

11 crystal system only 7 different types of unit cells. 14 standard (bravais) unit cells could describe all possible lattice networks crystal system cubic tetragonal orthorhombic axial lengths & interaxial angles a = b = c. = = = 90o a = b c. = = = 90o a b c. = = = 90o space lattice simple cubic body-centered cubic face-centered cubic simple tetragonal body-centered tetragonal simple orthorhombic body-centered orthorhombic base-centered orthorhombic face-centered orthorhombic rhombohedral a = b = c simple rhombohedral hexagonal monoclinic triclinic. = = 90o a = b c. = = 90o base-centered monoclinic a b c. 90o simple monoclinic simple hexagonal simple triclinic. 90% elemental metals crystallize into three crystal structures: Bcc coordination number = 8 total 2 atoms per unit cell. 3 atomic packing factor (apf) volume of atoms in unit cell. 55 coordination number = 12 total 4 atoms per unit cell. 2 the closest packing possible of spherical atoms cubic closest-packed.