Chp. 4 Vocab Flashcards
allotropy
The possibility of the existence of two or more different
crystal structures for a substance.
anion
A negatively charged ion
atomic packing factor (APF)
The fraction of the volume of a
unit cell that is occupied by hard-sphere atoms or ions.
body-centered cubic (BCC)
Within the cubic unit cell, atoms
are located at corner and cell center positions.
Bragg’s law
A relationship that stipulates the
condition for diffraction by a set of crystallographic planes.
cation
A positively charged ion.
coordination number
The number of atomic or ionic nearest
neighbors.
crystallinity
The state in which a periodic and
repeating atomic arrangement is achieved by molecular chain
alignment.
diffraction (x-ray)
Constructive interference of x-ray beams
scattered by atoms of a crystal.
face-centered cubic (FCC)
Within the cubic unit cell, atoms
are located at all corner and face-centered positions.
hexagonal close-packed (HCP)
The HCP unit cell is of hexagonal geometry
and is generated by the stacking of close-packed
planes of atoms.
octahedral position
The void space among close-packed, hardsphere
atoms or ions for which there are six nearest neighbors.
polymorphism
The ability of a solid material to exist in more
than one form or crystal structure.
tetrahedral position
The void space among close-packed, hardsphere
atoms or ions for which there are four nearest neighbors.