Ca ₁₄ FeAs ₁₁ – A structure comprising structural motifs of iron‐based superconductors and Ca‐As Zintl phases

Ca14FeAs11 is the first iron-containing representative of Ca14AlSb11 structure type and compound with isolated FeAs4 tetrahedra. It can be regarded as a salt-like containing [FeAs4]9− tetrahedra, linear [As3]7− units, As3− anions Ca2+ cations thus borderline between binary Fe−As intermetallics calcium arsenides. obtained by two-step high-temperature reaction, in which preformed FeAs alloy heated Ca presence additional As sealed silica tube. Structure determination from single crystals at 150 K reveal space group I41/acd (Z=8, a=15.6268(2) Å, c=20.9781(5) V=5122.79(15) Å3). Band calculations predict metallic properties strong contribution Fe orbitals to density states Fermi level.