Condensed [OPr_4]~(10+)and Discrete [AsO_3]~3- Ψ~1-Tetrahedrain Pr_5O_4Cl[AsO_3]_2

摘要

The oxide chloride arsenite Pr_5O_4Cl[AsO_3]_2was obtained as green crystals a by-product ofthe synthesis of PrOTAs oxide arsenides(T =late transition metal), starting from Pr_6O_(11), a transi-tion metal oxide, arsenic, and an NaCl/KCl flux. Pr_5O_4Cl[AsO_3]_2crystallizes with the monoclinicNd_5O_4Cl[AsO_3]_2-type structure, space group C2/m. The structure was refined from single-crystal diffractometer data: a = 12.4943(15), b = 5.6884(13) c = 9.0776(19) A,β = 116.61(0°, R(F) =0.0264, wR(F~2) = 0.0509, 542F~2values, and 52 variables. It is built up from corrugated layers ofedge- and corner-sharing [OPr_4]~(10+)tetrahedra, which are connectedviachloride anions. The spacebetween the layers is filled by these CL and discrete arsenite anions [AsO_3]~(3–)with lone pairs point-ing towards each other. The network of condensed [OPr_4]~(10+)tetrahedra is compared with the dif-ferent arrays in the oxide pnictides α-PrOZnP, and in β-PrOZnP. Arsenic lone pair energy bands,main interactions, and the spatial distribution were identified precisely using density functional the-ory (DFT). Among the three crystallographically different sites for praseodymium, one was foundnon-magnetic in these calculations.