Ln3Cu4P4O2: A New Lanthanide Transition Metal Pnictide Oxide Structure Type

A new type of lanthanide transition metal pnictide oxide, Ln{sub 3}Cu{sub 4}P{sub 4}O{sub 2} (for Ln = La, Ce, and Nd), is reported. The crystal structure is made from Ln{sub 2}O{sub 2} layers of the Pb{sub 2}O{sub 2} type stacked with layers of Cu{sub 2}P{sub 2} tetrahedra and indicates the existence of a homologous series of compounds with similar chemistry connecting the BiCuOSe and ThCr{sub 2}Si{sub 2} structure types. The resistivity of La{sub 3}Cu{sub 4}P{sub 4}O{sub 2} is metallic, with no superconductivity observed above 2 K. The Ce and Nd compounds have magnetic susceptibilities characteristic of the trivalent Lanthanides. No magnetic ordering is observed above 4.2 K.