Crystal Lattice Structures
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Introduction

Simple Cubic

Body Centered Cubic

Face Centered Cubic

Primitive FCC

Simple Hexagonal

Hexagonal Closest Packing

HCP Coordination

Cubic Closest Packing

CCP Coordination

Rhombohedral

2- & 3-Layer repeats

4-layer repeats

Tetrahedral Holes

Octahedral Holes

CsCl

NaCl

Halite

Fluorite

Zinc Blende

Exercises
Coordination in HCP
  Each host atom in an HCP lattice is surrounded by and touches 12 nearest neighbors, each at a distance of 2r:
  • There are six atoms in the planar hexagonal array (the central A layer);
  • There are three atoms in the B layer above the A layer;
  • There are three atoms in the B layer below the A layer.
The six atoms in the two B layers form a trigonal prism around the central atom in the A layer; the length of this prism is 2.CPIS.r.

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Steven F. Watkins, Department of Chemistry, Louisiana State University