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Strontium ferrate (Ruddlesden–Popper n = 2) Sr₃Fe₂O₇

Layered perovskite (Ruddlesden–Popper n = 2) · space group P₄/mmm (No. 123) · Z = 2

Symmetry elements and Wyckoff positions (interactive)

Strontium ferrate (Ruddlesden–Popper n = 2) in P4/mmm

Setting

Loading the group…

Model atom x

y

z

x = 0.10, y = 0.17, z = 0.08

Unit cell

Lattice constants: a = 3.874 Å, b = 3.874 Å, c = 40.314 Å; α = 90°, β = 90°, γ = 90°
Cell volume: 605.0 Å³
Atoms in the cell: 48 (O 28, Sr 12, Fe 8)
Formula units Z: 2
Calculated density: 5.34 g cm⁻³
Shortest contact: 1.693 Å

Coordination

O: CN 2 at 1.94 Å (1.71 Fe + 0.29 Sr)
Sr: CN 8 at 2.47 Å (7.67 O)
Fe: CN 5 at 1.77 Å (5 O)

About the structure

Double perovskite blocks — two layers of corner-sharing FeO₆ octahedra — separated by SrO rock-salt layers: the n = 2 member of Srₙ₊₁FeₙO₃ₙ₊₁; n = ∞ is SrFeO₃ perovskite itself.
The series shows how a 3D perovskite can be sliced into 2D blocks; the same n = 2 topology appears in the manganite Ca₃Mn₂O₇ and in the superconductor parent Sr₃Ru₂O₇.
Coordinates from the Crystallography Open Database, entry 2107053 (open data); hydrogen and water sites with partial occupancy below 0.5 are left out.

Atom positions (fractional, one cell)

Atom	x	y	z
O	0.0000	0.5000	0.2020
O	0.5000	0.0000	0.2020
O	0.0000	0.5000	0.7980
O	0.5000	0.0000	0.7980
Sr	0.0000	0.0000	0.2400
Sr	0.0000	0.0000	0.7600
O	0.0000	0.0000	0.4150
O	0.0000	0.0000	0.5850
O	0.0000	0.5000	0.3010
O	0.5000	0.0000	0.3010
O	0.0000	0.5000	0.6990
O	0.5000	0.0000	0.6990
O	0.0000	0.0000	0.5000
Fe	0.5000	0.5000	0.2930
Fe	0.5000	0.5000	0.7070
O	0.0000	0.0000	0.0930
O	0.0000	0.0000	0.9070
Fe	0.0000	0.0000	0.4570
Fe	0.0000	0.0000	0.5430
O	0.5000	0.5000	0.2490
O	0.5000	0.5000	0.7510
Sr	0.0000	0.0000	0.3420
Sr	0.0000	0.0000	0.6580
Sr	0.5000	0.5000	0.0000
O	0.5000	0.5000	0.3400
O	0.5000	0.5000	0.6600
O	0.5000	0.5000	0.1600
O	0.5000	0.5000	0.8400
Sr	0.5000	0.5000	0.4190
Sr	0.5000	0.5000	0.5810
O	0.0000	0.0000	0.0000
Sr	0.5000	0.5000	0.0970
Sr	0.5000	0.5000	0.9030
Fe	0.5000	0.5000	0.2030
Fe	0.5000	0.5000	0.7970
Sr	0.5000	0.5000	0.5000
O	0.0000	0.5000	0.4460
O	0.5000	0.0000	0.4460
O	0.0000	0.5000	0.5540
O	0.5000	0.0000	0.5540
Sr	0.0000	0.0000	0.1550
Sr	0.0000	0.0000	0.8450
Fe	0.0000	0.0000	0.0480
Fe	0.0000	0.0000	0.9520
O	0.0000	0.5000	0.0610
O	0.5000	0.0000	0.0610
O	0.0000	0.5000	0.9390
O	0.5000	0.0000	0.9390

Z, coordination numbers, distances, density and packing on this page are computed from these coordinates.

Other oxides & frameworks

Perovskite (ideal cubic)SrTiO₃ · ABO₃ Rhenium trioxideReO₃ · AB₃ SpinelMgAl₂O₄ · AB₂O₄ CorundumAl₂O₃ · A₂B₃ CupriteCu₂O · A₂B PyriteFeS₂ · AB₂ with S₂²⁻ pairs CalciteCaCO₃ · Carbonate MolybdeniteMoS₂ · Layered AB₂, 6:3 ScheeliteCaWO₄ · ABO₄ tetrahedral oxo-anion Magnetite (inverse spinel)Fe₃O₄ · Inverse spinel AB₂O₄ Ice Ih (oxygen framework)H₂O · Hydrogen-bonded network Barium titanate (tetragonal)BaTiO₃ · Ferroelectric perovskite YBCO superconductorYBa₂Cu₃O₇ · Oxygen-deficient triple perovskite Yttrium titanate (pyrochlore)Y₂Ti₂O₇ · Pyrochlore A₂B₂O₇ Potassium nickel fluorideK₂NiF₄ · Layered perovskite (Ruddlesden–Popper n = 1)Thallium cuprate Tl-2223 (superconductor)Tl₂Ba₂Ca₂Cu₃O₁₀ · Layered cuprate (triple CuO₂ layers)

Open Strontium ferrate (Ruddlesden–Popper n = 2) in the 3D viewer → · All structures