Crystal Lab › Pigments & minerals
Prussian blue (idealised) Fe₄[Fe(CN)₆]₃
Cyanide framework (double perovskite-like) · space group Fm-3m (No. 225) · Z = 4
Symmetry elements and Wyckoff positions (interactive)
Prussian blue (idealised) in Fm-3m
SettingLoading the group…
x = 0.10, y = 0.17, z = 0.08
Unit cell
- Lattice constants
- a = 10.170 Å, b = 10.170 Å, c = 10.170 Å; α = 90°, β = 90°, γ = 90°
- Cell volume
- 1051.9 ų
- Atoms in the cell
- 56 (Fe 8, C 24, N 24)
- Formula units Z
- 4
- Calculated density
- 1.69 g cm⁻³
- Shortest contact
- 1.220 Å
Coordination
- Fe²⁺ (C-bound)
- CN 6 at 1.93 Å (6 C)
- Fe³⁺ (N-bound)
- CN 6 at 1.93 Å (6 N)
- C
- CN 1 at 1.22 Å (1 N)
- N
- CN 1 at 1.22 Å (1 C)
About the structure
- A cubic framework of Fe²⁺–C≡N–Fe³⁺ bridges: low-spin Fe²⁺ bonded to six carbons, high-spin Fe³⁺ to six nitrogens, the two iron sites alternating like Na and Cl in rock salt.
- The intense blue is a Fe²⁺ → Fe³⁺ charge-transfer absorption through the cyanide bridge. Drawn as the ideal ordered framework; the real pigment has one-quarter of the [Fe(CN)₆] units missing, with water in the vacancies, which is why the formula is Fe₄[Fe(CN)₆]₃.
- Idealised ordered model built from the Wyckoff positions of the space group; not a diffraction refinement.
Atom positions (fractional, one cell)
| Atom | x | y | z |
|---|---|---|---|
| Fe Fe²⁺ (C-bound) | 0.0000 | 0.0000 | 0.0000 |
| Fe Fe²⁺ (C-bound) | 0.0000 | 0.5000 | 0.5000 |
| Fe Fe²⁺ (C-bound) | 0.5000 | 0.0000 | 0.5000 |
| Fe Fe²⁺ (C-bound) | 0.5000 | 0.5000 | 0.0000 |
| Fe Fe³⁺ (N-bound) | 0.5000 | 0.5000 | 0.5000 |
| Fe Fe³⁺ (N-bound) | 0.5000 | 0.0000 | 0.0000 |
| Fe Fe³⁺ (N-bound) | 0.0000 | 0.5000 | 0.0000 |
| Fe Fe³⁺ (N-bound) | 0.0000 | 0.0000 | 0.5000 |
| C | 0.1900 | 0.0000 | 0.0000 |
| C | 0.8100 | 0.0000 | 0.0000 |
| C | 0.0000 | 0.1900 | 0.0000 |
| C | 0.0000 | 0.8100 | 0.0000 |
| C | 0.0000 | 0.0000 | 0.1900 |
| C | 0.0000 | 0.0000 | 0.8100 |
| C | 0.1900 | 0.5000 | 0.5000 |
| C | 0.8100 | 0.5000 | 0.5000 |
| C | 0.0000 | 0.6900 | 0.5000 |
| C | 0.0000 | 0.3100 | 0.5000 |
| C | 0.0000 | 0.5000 | 0.6900 |
| C | 0.0000 | 0.5000 | 0.3100 |
| C | 0.6900 | 0.0000 | 0.5000 |
| C | 0.3100 | 0.0000 | 0.5000 |
| C | 0.5000 | 0.1900 | 0.5000 |
| C | 0.5000 | 0.8100 | 0.5000 |
| C | 0.5000 | 0.0000 | 0.6900 |
| C | 0.5000 | 0.0000 | 0.3100 |
| C | 0.6900 | 0.5000 | 0.0000 |
| C | 0.3100 | 0.5000 | 0.0000 |
| C | 0.5000 | 0.6900 | 0.0000 |
| C | 0.5000 | 0.3100 | 0.0000 |
| C | 0.5000 | 0.5000 | 0.1900 |
| C | 0.5000 | 0.5000 | 0.8100 |
| N | 0.3100 | 0.0000 | 0.0000 |
| N | 0.6900 | 0.0000 | 0.0000 |
| N | 0.0000 | 0.3100 | 0.0000 |
| N | 0.0000 | 0.6900 | 0.0000 |
| N | 0.0000 | 0.0000 | 0.3100 |
| N | 0.0000 | 0.0000 | 0.6900 |
| N | 0.3100 | 0.5000 | 0.5000 |
| N | 0.6900 | 0.5000 | 0.5000 |
| N | 0.0000 | 0.8100 | 0.5000 |
| N | 0.0000 | 0.1900 | 0.5000 |
| N | 0.0000 | 0.5000 | 0.8100 |
| N | 0.0000 | 0.5000 | 0.1900 |
| N | 0.8100 | 0.0000 | 0.5000 |
| N | 0.1900 | 0.0000 | 0.5000 |
| N | 0.5000 | 0.3100 | 0.5000 |
| N | 0.5000 | 0.6900 | 0.5000 |
| N | 0.5000 | 0.0000 | 0.8100 |
| N | 0.5000 | 0.0000 | 0.1900 |
| N | 0.8100 | 0.5000 | 0.0000 |
| N | 0.1900 | 0.5000 | 0.0000 |
| N | 0.5000 | 0.8100 | 0.0000 |
| N | 0.5000 | 0.1900 | 0.0000 |
| N | 0.5000 | 0.5000 | 0.3100 |
| N | 0.5000 | 0.5000 | 0.6900 |
Z, coordination numbers, distances, density and packing on this page are computed from these coordinates.
Other pigments & minerals
Open Prussian blue (idealised) in the 3D viewer → · All structures