Dibarium tricadmium bis-muthide(-I,-III) oxide, Ba(2)Cd(3-δ)Bi(3)O.

Ba(2)Cd(2.13)Bi(3)O, a new bis-muthide(-I,-III) oxide, crystallizes with a novel body-centered tetra-gonal structure (Pearson code tI36). The crystal structure contains eight crystallographically unique sites in the asymmetric unit, all on special positions. Two Ba, one Cd and two Bi atoms have site symmetry 4mm, the third Bi atom has mmm. and the O atom has m2 symmetry; the second Cd site (2mm. symmetry) is not fully occupied. The layered structure is complex and can be considered as an inter-growth of two types of slabs, viz. BaCdBiO with the ZrCuSiAs type and BaCd(2)Bi(2) with the CeMg(2)Si(2) type.