K8IN10HG - A ZINTL PHASE WITH ISOLATED IN10HG CLUSTERS

The title compound results from the substitution of one mercury atom f or indium in the known metallic K8In11 [8K+ + In-11(7-) + e-]. It cont ains the same isolated eleven-atom clusters as before, pentacapped tri gonal prisms compressed along the three-fold axis, but with mercury di sordered over the trigonal prismatic sites (P6(3)/m, Z = 2, a = 9.9812 (4) angstrom, c = 16.851(1) angstrom, R/R(w) = 2.4/2.8%). The cluster In10Hg8- is likewise hypoelectronic and requires the 2n-4 = 18 skeleta l bonding electrons available for this stoichiometry. The close-packed layers of clusters are again separated by double layers of potassium, but these follow an h.c.p. order rather than the c.c.p. arrangement f ound in K8In11. The phase is diamagnetic (approximately -3.5 x 10(-4) emu mol-1), in contrast to the Pauli-like behavior of K8In11, but it t oo exhibits a conductivity characteristic of a poor metal or a semimet al, rho295 approximately 270 muOMEGA-1 cm-1 with a coefficient of +0.4 8% deg-1.