ScFe 5 P 3 , ScRu 6 P 4 , U 2 Mo 30 P 19 , 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. ScFe 5 P 3 , Sc(Ta 0.18 Fe 0.82 )Fe 4 P 3 , and ZrFe 5 P 3 are isotypic with YCo 5 P 3 . 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 ScRu 6 P 4 (α‐UCr 6 P 4 type) was refined from single‐crystal data: P $\bar{6}$ m 2, 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 ErRu 6 P 4 and ZrCr 6 P 4 . However, single‐crystal film data for the latter compound suggest a superstructure with a doubling of the hexagonal axis. The new compound Nd 2 Ru 12 P 7 is shown from Guinier powder data to crystallize with a hexagonal Zr 2 Fe 12 P 7 type structure. X‐ray powder data also confirm Zr 2 Ru 12 P 7 and SmCo 3 P 2 to crystallize with Zr 2 Fe 12 P 7 and HoCo 3 P 2 type structures, respectively. The crystal structure of the phosphide U 2 Cr 30 P 19 is confirmed to be isotypic with Zr 2 Cr 30 P 19 . The same structure was found for the new compound U 2 Mo 30 P 19 . The crystal structures of these and other compounds with a metal to phosphorus ratio close to 2:1 are briefly discussed including that of LiCo 6 P 4 .