Crystal Structure Flashcards
(19 cards)
Arrangement of the atoms in a material into a regular repeatable pattern
Crystal Structure
Collective term for 14 known crystal structures
Bravais Crystal Structures
Composed of atoms on the lattice points of a cube, thus having a total of one atom
Simple Cubic
Composed of 2 atoms; a single center atom plus 1/8 from each corner
Body-Centered Cubic (BCC)
Composed of 4 atoms; for each phase, half atoms, plus 1/8 from each corners
Face-Centered Cubic (FCC)
aka Close Cubic Packed (CCP)
Composed of 6 atoms; 3 center atoms, 1/2 atoms from bottom and top, and 1/6 atoms from each vertices of hexagon
Hexagonal Close Packed (HCP)
Number of atoms that a central atom holds as its nearest neighbors in a crystal
Coordination Number
Sum of the sphere volumes of all atoms within a unit cell
Atomic Packing Factor (APF)
efficiency of the unit cell
Shorthand notation to describe certain crystallographic planes in a material
Miller Indices
Calculate the volume of an FCC unit cell in terms of the atomic radius R
V = 16R^3sqrt(2)
Lattice irregularity having one or more of its dimensions on the or of an atomic diameter
Crystalline defect
Atom is missing in the lattice structure
Point Defect
The defect which takes place due to imperfect packing of atoms during crystallization
Point Defect
An atom from the crystal that is crowded into an interstitial site
Self-interstitial
Type of Defect
Type of point defect
Frenkel Defect
Missing one cation and one anion
leaving vacancies
Schottky Imperfection
Misalignment defect of atoms
Dislocation
Type of Defect
A linear defect that centers around the line that is defined along the end of the extra half-plane of atoms
Edge Dislocation
Type of Defect
Extra half plane of atoms
Edge dislocation
