New rhodium compounds with the LiCo6P4 type structure

Five new phosphides and arsenides respectively of the formula ARh(6)X(4) (A : Mg-Sr, Yb; X: P, As) were prepared by heating mixtures of the elements an d investigated by means of single crystal X-ray methods. They are isotypic and crystallize in the LiCo6P4 type structure(P<(6)over bar >m2; Z = 1) (la ttice constants see "Inhaltsubersicht"). The compounds belong to the large family of phosphides and arsenides, which have a metal:non-metal ratio of a bout 2:1. Their structures are characterized by the environment of phosphor us and arsenic respectively, which is composed of trigonal prisms of metal atoms with additional metal atoms capping the rectangular faces of the pris ms.