Unit cell
- Lattice constants
- a = 5.463 Å, b = 5.463 Å, c = 5.463 Å; α = 90°, β = 90°, γ = 90°
- Cell volume
- 163.0 ų
- Atoms in the cell
- 12 (Ca 4, F 8)
- Formula units Z
- 4
- Calculated density
- 3.18 g cm⁻³
- Shortest contact
- 2.366 Å
Coordination
- Ca
- CN 8 at 2.37 Å (8 F)
- F
- CN 4 at 2.37 Å (4 Ca)
About the structure
- ccp array of Ca²⁺ with F⁻ in every tetrahedral hole.
- Coordination 8:4: Ca in a cube of F, F in a tetrahedron of Ca.
- Equally: a simple cubic array of F⁻ with Ca²⁺ in half the cubic holes.
- BaF₂, SrF₂, CeO₂, UO₂, ZrO₂ (cubic) share this structure.
Atom positions (fractional, one cell)
| Atom | x | y | z |
|---|---|---|---|
| Ca | 0.0000 | 0.0000 | 0.0000 |
| Ca | 0.0000 | 0.5000 | 0.5000 |
| Ca | 0.5000 | 0.0000 | 0.5000 |
| Ca | 0.5000 | 0.5000 | 0.0000 |
| F | 0.2500 | 0.2500 | 0.2500 |
| F | 0.2500 | 0.7500 | 0.7500 |
| F | 0.7500 | 0.2500 | 0.7500 |
| F | 0.7500 | 0.7500 | 0.2500 |
| F | 0.7500 | 0.7500 | 0.7500 |
| F | 0.7500 | 0.2500 | 0.2500 |
| F | 0.2500 | 0.7500 | 0.2500 |
| F | 0.2500 | 0.2500 | 0.7500 |
Z, coordination numbers, distances, density and packing on this page are computed from these coordinates.