Using a high-temperature ampoule technique and lead metal as a flux, we have grown single crystals and determined crystal structures from single-crystal X-ray diffraction data of two metal-rich phosphides, Sr5Pt12P9 (P 2 1/m, a = 6.1472(3) Å, b = 25.1713(13) Å, c = 6.4635(3) Å, β = 99.604(2)°, Z = 2, R 1 = 0.0326, wR 2 = 0.0786) and BaPt3P2 (P 212121 , a = 6.3605(6) Å, b = 6.8541(7) Å, c = 11.3493(12) Å, Z = 4, R 1 = 0.0231, wR 2 = 0.0501). Both compounds belong to their own structure types and feature 3D networks of Pt and P atoms, with the channels occupied by alkaline earth metal cations. Density functional theory calculations reveal Sr5Pt12P9 to be a metal, while BaPt3P2 is a narrow-gap semiconductor with a band gap of 0.24 eV. Bonding analysis shows that both compounds feature networks of prominent covalent localized Pt–P bonds, responsible for their structural stability, as well as additional weaker and, likely, less localized Pt–Pt interactions.

Three quaternary phosphide platinides, Ca2Pt7AlP3.00(4), Ca2Pt7TiP3.24(4), and Ca2Pt7ZnP2.78(2), were synthesized by a high-temperature technique using lead as a flux. According to the single-crystal diffraction data, they are isotypic and crystallize...

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A series of solid solutions in the PdTe–PdBi system with general formula [Formula: see text]Bix ([Formula: see text], 0.5, 0.67) with the structure based on the NiAs type were synthesized by a high-temperature ampoule technique. These compounds, along with their parent binaries, PdTe and PdBi, were tested as promoters for the standard Co/Al2O3 catalytic system in the Fischer–Tropsch synthesis. It is shown that the addition of PdTe and [Formula: see text]Bix to the standard catalyst increases both yield and selectivity with respect to the liquid phase. At the same time, the addition of PdBi does not only improve catalytic activity, but also slightly inhibits it. Another positive effect of the PdTe and [Formula: see text]Bix addition is the shift in the conversion products toward the diesel and wax fractions. Chemical bonding analysis in orbital and direct space indicates that the addition of Bi to PdTe might increase the localized bonding.

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