ScFe₅P₃, ScRu₆P₄, U₂Mo₃₀P₁₉, and other ternary phosphides with a metal to phosphorus ratio close to 2:1

The title compounds and several other new ternary phosphides - all with closely related crystal structures - were prepared mostly by using elemental tin as a flux. ScFe₅P₃, Sc(Ta_0.18Fe_0.82)Fe₄P₃, and ZrFe₅P₃ are isotypic with YCo₅P₃. The crystal structure of the tantalum containing compound was determined from single-crystal X-ray counter data: space group Pnma, a = 1212.5(2) pm, b = 363.0(2) pm, c = 1052.2(2) pm with a residual R = 0.036 for 505 unique structure factors and 30 variable parameters. The Ta atoms occupy only that Fe site with the highest coordination number. The crystal structure of ScRu₆P₄ (α-UCr₆P₄ type) was refined from single-crystal data: P anti 6m2, a = 690.0(2) pm, c = 362.5(3) pm; R = 0.023 for 226 F_o and 15 variables. The same structure was also found from Guinier powder data for ErRu₆P₄ and ZrCr₆P₄. However, single-crystal film data for the latter compound suggest a superstructure with a doubling of the hexagonal axis. The new compound Nd₂Ru₁₂P₇ is shown from Guinier powder data to crystallize with a hexagonal Zr₂Fe₁₂P₇ type structure. X-ray powder data also confirm Zr₂Ru₁₂P₇ and SmCo₃P₂ to crystallize with Zr₂Fe₁₂P₇and HoCo₃P₂ type structures, respectively. The crystal structure of the phosphide U₂Cr₃₀P₁₉ is confirmed to be isotypic with Zr₂Cr₃₀P₁₉. The same structure was found for the new compound U₂Mo₃₀P₁₉. The crystal structures of these and other compounds with a metal to phosphorus ratio close to 2:1 are briefly discussed including that of LiCo₆P₄. (Copyright copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)