Lanthanum iron arsenide oxide LaFeAsO

Unit cell

Lattice constants

a = 4.035 Å, b = 4.035 Å, c = 8.741 Å; α = 90°, β = 90°, γ = 90°

Cell volume

142.3 ų

Atoms in the cell

8 (La 2, Fe 2, As 2, O 2)

Formula units Z

2

Calculated density

3.42 g cm⁻³

Shortest contact

2.367 Å

Coordination

La

CN 4 at 2.37 Å (4 O)

Fe

CN 4 at 2.41 Å (4 As)

As

CN 4 at 2.41 Å (4 Fe)

O

CN 4 at 2.37 Å (4 La)

About the structure

• Alternating layers of edge-sharing FeAs₄ tetrahedra and edge-sharing OLa₄ tetrahedra, stacked along c: the parent of the iron-pnictide superconductors.
• Fluoride doping on the oxide site (LaFeAsO₁₋ₓFₓ, T꜀ = 26 K, 2008) started the second high-T꜀ family after the cuprates; the same tetrahedral Fe layer runs through all of them.
• Coordinates from the Crystallography Open Database, entry 4107570 (open data); hydrogen and water sites with partial occupancy below 0.5 are left out.

Atom positions (fractional, one cell)

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