Unit cell
- Lattice constants
- a = 5.550 Å, b = 5.550 Å, c = 5.550 Å; α = 90°, β = 90°, γ = 90°
- Cell volume
- 171.0 ų
- Atoms in the cell
- 12 (O 4, Na 8)
- Formula units Z
- 4
- Calculated density
- 2.41 g cm⁻³
- Shortest contact
- 2.403 Å
Coordination
- O
- CN 8 at 2.40 Å (8 Na)
- Na
- CN 4 at 2.40 Å (4 O)
About the structure
- Fluorite with the ions swapped: ccp array of O²⁻ with Na⁺ in every tetrahedral hole.
- Coordination 4:8.
- Li₂O, K₂O, Na₂S, K₂S share this structure.
Atom positions (fractional, one cell)
| Atom | x | y | z |
|---|---|---|---|
| O | 0.0000 | 0.0000 | 0.0000 |
| O | 0.0000 | 0.5000 | 0.5000 |
| O | 0.5000 | 0.0000 | 0.5000 |
| O | 0.5000 | 0.5000 | 0.0000 |
| Na | 0.2500 | 0.2500 | 0.2500 |
| Na | 0.2500 | 0.7500 | 0.7500 |
| Na | 0.7500 | 0.2500 | 0.7500 |
| Na | 0.7500 | 0.7500 | 0.2500 |
| Na | 0.7500 | 0.7500 | 0.7500 |
| Na | 0.7500 | 0.2500 | 0.2500 |
| Na | 0.2500 | 0.7500 | 0.2500 |
| Na | 0.2500 | 0.2500 | 0.7500 |
Z, coordination numbers, distances, density and packing on this page are computed from these coordinates.