V. Queneau et Sc. Sevov, SYNTHESIS AND STRUCTURE OF THE ZINTL-PHASE K4PB9 CONTAINING ISOLATED PB-9(4-) CLUSTERS OF 2 DIFFERENT GEOMETRIES, Inorganic chemistry, 37(6), 1998, pp. 1358-1360
The first nine-atom deltahedral clusters of lead in the solid state ar
e found in the Zintl-phase K4Pb9. The compound crystallizes in the mon
oclinic space group P2(1)/m, Z = 4, with a = 9.648(3) Angstrom, b = 13
.243(5) Angstrom, c = 15.909(8) Angstrom, and beta = 103.24(4)degrees.
The isolated Pb-9(4-) clusters are of two different geometries, a mon
ocapped square antiprism and an elongated tricapped trigonal prism.