| K0.75[FeII3.75FeIII1.25(HPO3)6]·0.5H2O | Dx = 3.195 Mg m−3 |
| Mr = 797.45 | Mo Kα radiation, λ = 0.71073 Å |
| Trigonal, P3c1 | Cell parameters from 3002 reflections |
| Hall symbol: -P 3 2"c | θ = 2.3–28.0° |
| a = 10.1567 (5) Å | µ = 5.14 mm−1 |
| c = 9.2774 (6) Å | T = 100 K |
| V = 828.82 (8) Å3 | Prism, black |
| Z = 2 | 0.29 × 0.05 × 0.04 mm |
| F(000) = 779 |