Geometry of Crystals

Geometry of CrystalsCrystal is a solid composed of atoms, ions or molecules that demonstrate long range periodic order in three dimensionsThe Crystalline StateState of MatterFixed VolumeFixed ShapeOrderPropertiesGasNoNoNoIsotropicLi quidYesNoShort-rangeIsotropicSolid (amorphous)YesYesShort-rangeIsotropicSol id (crystalline)YesYesLong-rangeAnisotropic Crystal LatticeNot only atom, ion or molecule positions are repetitious there are certain symmetry relationships in their constantsa, bCrystallinestructure=Basis+LatticeabABC A tomsCrystal LatticeaOne-dimensional lattice with lattice parameter aaaru abTwo-dimensional lattice with lattice parameters a,band ab bar uCrystal Latticecbarwu Crystal LatticeLattice vectors, lattice parameters and interaxial angles Lattice vectorabcLattice parameterabcInteraxial angle bacabcA lattice is an array of points in space in which the environment of each point is identicalCrystal LatticeLatticeNot a latticeCrystal LatticeUnit cell content Coordinates of all atoms Types of atoms Site occupancy Individual displacement parameters0x1x2x3y1y2y3 Crystal LatticeUsually unit cell has more than one molecule or group of atoms They can be represented by symmetry operatorsrotationSymmetrySymmetry is a proper

Point Group Centrosymmetric Point Group Minimum Rotational Symmetry Triclinic One 1-fold Monoclinic One 2-fold Orthorombic Three 2-folds Tetragonal One 4-fold Trigonal One 3-fold Hexagonal One 6-fold Cubic Four 3-folds 1 1 2,m 2m 4, 422, 4, 4mm, 42m mmm 222,mm2 m,4 mmm 3,32,3m,3 m 6, 622, 6, 6mm, 6m2 6 m, 6 mmm 23, 432, 43m m3,m3m Crystal Symmetry

Loading..

Tags:

  Group

Information

Related search queries