Download Definitions for Concept Map

Solid State Properties
 Holes are free space within a packing structure; usually filled with smaller cations for
ionic solids.
→ Octahedral hole is
coordinated by six anions.
→ Tetrahedral hole is
coordinated by four
anions.
 Formula Unit of Ionic
Compound is the empirical
formula of an ionic or covalent
network solid; lowest whole
number ratio of ions represented in an ionic compound.
 Interstitial sites are empty spaces between atoms; geometry is a square/four-coordinate.
 Crystalline solids are a highly regular arrangement of atoms, ions and molecules in a
lattice formation; opposite to Amorphous solid.
→ Different types exist including extended/network covalent, ionic, metallic, and
molecular.
→ Study their structures through x-ray diffraction.
→ Crystallinity is a repeating unit/unit cell.
 Face Centered Cubic (FCC) lattice points at the corners and in the
middle of each face.
→ Cubic lattice formation.
 Body Centered Cubic (BCC), lattice points at corners and in middle of
cube.
→ Cubic lattice formation.
 Amorphous solid is a short range order, no repeating pattern, extensively
disordered arrangement of atoms, ions and molecules; non-crystalline (e.g. glasses).
→ Glasses is a type of amorphous solid.
 Metallic solids.
→ Coordination number is when atoms are packed around
each other to maximize the bonding in a metal by
maximizing the number of nearest neighbours and
minimizing the volume.
→ Closest packing is the most efficient form of packing; if we treat the atoms as
spheres and consider all the atoms in the solid to be of equal size (as is the case
for elemental metals).
→ The {ABAB... } type stacking of close packed layers is called Hexagonal close
packing (HCP) because the smallest lattice repeat is a Primitive Hexagonal unit
cell; coordination number of 74%.
→ Cubic closest packing (CCP) is an alternate method of
stacking where the third layer lies in a unique position, in this
way an "ABCABC..." close packed layer sequence can be
created; coordination number of 74%.
→ Body centered cubic (BCC) is not close packed, atoms at corners and body center
of cube; coordination number of 68%.
→ Simple cubic is not close packed, primitive or simple cubic cell
with atoms only at the corners; rare packing arrangement for
metals (e.g. polonium); coordination number of 52%.