Crystal structure and magnetic properties of the new intermetallic Ce2Pt9Al16

The crystal structure of the ternary intermetallic Ce2Pt9Al16 has been determined from single crystal X-ray data. It crystallizes in a new structure type in the orthorhombic system, with cell parameters a = 4.1597(9), b = 11.910(3), c = 18.186(4) إ, space group Immm, Z = 2, Pearson code oI54. Cerium atom has a hexagonal prismatic coordination, tetragonal prisms are typical for coordination environment of platinum and aluminium atoms. The structure is described as a stacking of Ce-filled hexagonal prisms and two types of empty tetragonal prisms. Magnetic susceptibility measurements reveal antiferromagnetic ordering below TN = 3 K.