Ca(10)Pt(7)Tt(3) (Tt = Si, Ge): New Platinide Phases Featuring Electron-Rich 4c-6e Bonded [Pt(7)Tt(3)](20-) Intermetalloid Clusters.
Two new phases Ca(10)Pt(7)Tt(3) (with Tt = Si, Ge) were obtained by reacting stoichiometric mixtures of the elements at high temperature. Their structures were refined from single crystal X-ray diffraction data. They are isostructural and crystallize in the Ba(10)Al(3)Ge(7) type structure, space group P6(3)/mcm (No. 193) with a = b = 8.7735(3) Å, c = 13.8260(5) Å, V = 921.66(6) Å(3), Z = 2 for Tt