Crystal Lab › Elements & packing
Face-centred cubic (ccp) Cu
Elemental · space group Fm-3m (No. 225) · Z = 4
Unit cell
- Lattice constants
- a = 3.615 Å, b = 3.615 Å, c = 3.615 Å; α = 90°, β = 90°, γ = 90°
- Cell volume
- 47.2 ų
- Atoms in the cell
- 4 (Cu 4)
- Formula units Z
- 4
- Calculated density
- 8.93 g cm⁻³
- Shortest contact
- 2.556 Å
- Packing efficiency
- 74.0 %
Coordination
- Cu
- CN 12 at 2.56 Å (12 Cu)
About the structure
- Cubic close packing: layers stack ABCABC along the body diagonal.
- Atoms touch along the face diagonal: √2·a = 4r, packing efficiency ≈ 74% (the maximum for equal spheres).
- Per atom: 1 octahedral hole and 2 tetrahedral holes.
- Cu, Ag, Au, Al, Ni, Pt, Pb adopt this structure.
Atom positions (fractional, one cell)
| Atom | x | y | z |
|---|---|---|---|
| Cu | 0.0000 | 0.0000 | 0.0000 |
| Cu | 0.0000 | 0.5000 | 0.5000 |
| Cu | 0.5000 | 0.0000 | 0.5000 |
| Cu | 0.5000 | 0.5000 | 0.0000 |
Z, coordination numbers, distances, density and packing on this page are computed from these coordinates.
Other elements & packing
Simple cubicPo · ElementalBody-centred cubicW · ElementalHexagonal close-packedMg · ElementalDiamondC · Covalent networkGraphiteC · Covalent layers
Open Face-centred cubic (ccp) in the 3D viewer → · All structures