Li₂Pt₃Se₄. A new lithium platinum selenide with jagueite-type crystal structure by multianvil high-pressure/high-temperature synthesis

The monoclinic lithium platinum selenide Li₂Pt₃Se₄ was obtained via a multianvil high-pressure/high-temperature route at 8 GPa and 1200 C starting from a stoichiometric mixture of lithium nitride, selenium, and platinum. The structure of the ternary alkali metal-transition metal-selenide was refined from single-crystal X-ray diffractometer data: P2₁/c (no. 14), a=525.9(2), b=1040.6(2), c=636.5(2) pm, β=111.91(1) , R1=0.0269, wR2=0.0569 (all data) for Li₂Pt₃Se₄. Furthermore, the isostructural mineral phases jagueite (Cu₂Pd₃Se₄) and chrisstanleyite (Ag₂Pd₃Se₄) were reinvestigated in their ideal stoichiometric ratio. The syntheses of the mineral phases were also carried out under multianvil conditions. Single-crystal data revealed a hitherto not described structural disorder of the transition metal atoms.