ScFe₅P₃, ScRu₆P₄, U₂Mo₃₀P₁₉, and Other Ternary Phosphides with a Metal to Phosphorus Ratio close to 2:1

Abstract

U2Mo30P19 (VIII) are prepared from mixtures of the elements in most cases with elemental Sn as a flux (alumina crucibles, 650-950 C, 7-10 d). The phosphides are characterized by powder and single crystal XRD. Compounds (I), (II), and (III) crystallize with the YCo 5 P 3 -type structure in the orthorhombic space group Pnma (Z = 4 for (II)). (IV-VI) crystallize with the -UCr 6 P 4 (LiCo 6 P 4 ) structure type in the hexagonal space group P6m2 (Z = 1 for (IV)). Compound (VII) crystallizes in the hexagonal space group P6 with the Zr 2 Fe 12 P 7 -type structure. (VIII) crystallizes in the hexagonal space group P6 with the U 2 Cr 30 P 19 (Zr 2 Cr 30 P 19 ) structure type. The crystal structures of these compounds with a metal to phosphorus ratio close to 2:1 are briefly discussed. -(JEITSCHKO*, W.; ALBERING, J. H.; BRINK, R.; JAKUBOWSKI-RIPKE, U.; REINBOLD, E. J.; Z. Anorg. Allg. Chem. 640 (2014) 12-13, 2449-2457 (NH 3 stream, 760 C, 1 h; 43% yield). As a representative of the anatase structure (aristotype) -TaON crystallizes in the tetragonal space group I4 1 /amd (Z = 4, powder XRD). An irreversible phase transformation to baddeleyite-type -TaON is observed between 800 and 850 C. While quantum-chemical calculations confirm the metastable character of -TaON, its transformation to -TaON is kinetically controlled. The anion distribution of the anatase-type phase is theoretically studied. Configurations with maximum N-N distances are shown to be most stable. The calculated band edge energies indicate that -TaON is a promising photocatalyst for redox reactions, e.g. water splitting. -Crystals of the title compound are prepared by condensation of NH 3 onto a mixture of Na 2 Cs 2 Ge 9 (obtained from the elements at 743.15 K for 72 h) and dibenzo-18-crown-6, followed by storage of the reaction mixture for one year at 235.15 K. The compound crystallizes in the monoclinic space group P2 1 /m with Z = 8. The coordination environments of the Cs cations contain three to four clusters, coordinating via their corners, edges, or triangular faces, and additionally three to six ammonia molecules. The first coordination sphere of cationic sites, which are fully occupied by Na is built by five ammonia molecules in a distorted trigonal bipyramidal manner. There are also mixed Na/Cs cation sites in which four ammonia molecules coordinate to Cs, whereas in the case of Na, one additional ammonia molecule is present. -(GAERTNER, S.; SUCHENTRUNK, C.; KORBER*, N.; Acta Crystallogr., Sect. C: Cryst. Struct. Commun. 70 (2014) (x = 0, 0.1, 0.23, 0.4) nanoflowers are prepared by hydrothermal treatment of LuCl 3 , BiCl 3 , and Te with NaBH 4 as reductant and EDTA as complexing agent (autoclave, 433 K, 24 h). The obtained nanopowders are pelletized by hot pressing, and the thermoelectric properties are investigated in relation to the Lu levels. The results show that Lu doping reduces the electrical resistivity largely, while it does not affect the Seebeck coefficient very much and therefore, results in a high power factor. Because th...

Ternary Laves phases Sc0.22(1)Ta0.78(1)Fe2 and Sc0.63(1)In0.37(1)Co2 – coloring variants of the MgZn2 and MgNi2 type

“…It is also worthwhile to note that scandium is often purified by distillation in tantalum apparatus and small amounts of tantalum can be observed in the distilled metal. This was observed during the synthesis of Sc(Ta 0.18 Fe 0.82 )Fe 4 P 3 [59] …”