A Further Extension of Pnictide Oxide Chemistry – Synthesis and Structure of La 2 AuP 2 O

The phosphide oxide La 2 AuP 2 O was synthesized from lanthanum filings, dried La 2 O 3 , gold pieces, and ground red phosphorus in the ideal 1.33:0.33:1:2 ratio in an evacuated silica tube at 1473 K. Small single crystals were obtained by recrystallization in a NaCl/KCl flux. The structure was determined on the basis of single‐crystal X‐ray diffractometer data: new type, C 2/ m , a = 1537.3(3), b = 427.39(8), c = 1009.2(2) pm, β = 131.02(1) °, wR 2 = 0.046, 1102 F 2 values, 38 variables. La 2 AuP 2 O contains two striking structural motifs: The oxygen atoms are located in La 4 tetrahedra. The latter are cis ‐edge‐shared forming polymeric cationic [La 2 O] 4+ chains. These cationic units are separated and charge‐balanced by [AuP 2 ] 4– polyanions which have monovalent gold in distorted trigonal planar phosphorus coordination. Two crystallographically independent phosphorus sites occur in the polyanion, i.e. isolated P 3– besides dumb‐bells P 2 4– (P2–P2 223 pm). La 2 AuP 2 O, which crystallizes in the form of ruby red transparent crystals, is an electron precise phosphide oxide (4La 3+ )(2Au + )(2P 3– )(P 2 4– )(2O 2– ).