title: Rare-earth manganese copper phosphides REMnCu4P3 (RE = Gd-Ho): the first quaternary ordered variants of the YCo5P3-type structure.
abstract: The quaternary rare-earth phosphides REMnCu(4)P(3) (RE = Gd-Ho) were obtained from direct reactions of the elements at 800 °C. They are the first examples in which ordering of two different transition-metal atoms takes place within the orthorhombic YCo(5)P(3)-type structure [Pearson symbol oP36, space group Pnma, Z = 4; a = 12.667(2)-12.6489(4) Å, b = 3.8119(7)-3.7755(1) Å, and c = 10.895(2)-10.8632(4) Å for RE = Gd-Ho]. Columns of trigonal prisms centered by P atoms are connected in propellor-shaped units in zigzag arrangements to generate square-pyramidal (CN5) sites that are occupied by Mn atoms and tetrahedral sites (CN4) that are occupied by Cu atoms. Spin-polarized band-structure calculations predict that the hypothetical compound YMnCu(4)P(3) will exhibit magnetic ordering. Electrical resistivity measurements on TbMnCu(4)P(3) indicate a poor metal.
authors.affiliation: Department of Chemistry, University of Alberta , Edmonton, Alberta, Canada T6G 2G2.
authors.forename: Krishna K
authors.initials: KK
authors.lastname: Ramachandran
authors.forename: Stanislav S
authors.initials: SS
authors.lastname: Stoyko
authors.forename: C Scott
authors.initials: CS
authors.lastname: Mullen
authors.forename: Arthur
authors.initials: A
authors.lastname: Mar