ON THE FIRST OXOPALLADAT-ARSENATE - KMG3P D(ASO4)(3)

Single crystals of KMg3Pd(AsO4)(3) have been prepared by solid state r eactions below the melting point of the reaction mixture. This compoun d crystallizes isotypic to the mineral Johillerite with monoclinic sym metry, space group C-2h(6)-C2/c, a = 12.098(3)Angstrom, b = 12.853(5)A ngstrom, c = 6.688(3)Angstrom, beta = 112.92(3)degrees, Z = 4. The cry stal structure is characterized by AsO4 tetrahedra, isolated planar bu t twisted PdO4 polygons, MgO6 octahedra and a 2+4+2-coordination of po tassium. From the point of view of crystal chemistry KMg3Pd(AsO4)(3) b oth belongs to the arsenates and oxopalladates(II).