Crystal Growth and Structures of Three New Platinates: Ln\u3csub\u3e3\u3c/sub\u3eNaPtO\u3csub\u3e7\u3c/sub\u3e (Ln = La, Nd) and La\u3csub\u3e4\u3c/sub\u3ePtO\u3csub\u3e7\u3c/sub\u3e

Single crystals of three lanthanide containing platinates, La3NaPtO7, Nd3NaPtO7 and La4PtO7, were grown from carbonate fluxes. La3NaPtO7 and Nd3NaPtO7 crystallize in the trigonal space group R3¯c with lattice parameters of a = 5.7458(2) Å and c = 35.650(1) Å, and a = 5.6862(5) Å and c = 34.896(3) Å, respectively. La4PtO7 crystallizes in the monoclinic space group I2/m with lattice parameters of a = 9.799(1) Å, b = 4.0014(5) Å, c = 9.491(1) Å and β = 91.759(5)°. La3NaPtO7 and Nd3NaPtO7 are the first all-platinum members of the [AnBn−1O3n][A2O] family of oxides. The difference in structure types of the three compounds arises from the size of the alkali metal cations present in the fluxes. Synthetic conditions as well as the structure differences between these platinates are discussed