The unconventional semiconductors represent two novel structure types of polythiometalates: syntheses, structures and electrical properties of {[W3Ag3S12]center dot[La(DMAC)(5)(H2O)(3)center dot(DMAC)(4)]}(n) and {[W8Ag10S32]center dot[M(DEF)(8)](2)}(n) (M = La, Nd)

Polymeric transition metal chalcogenides have attracted much attention beca use of their possible properties directly derived from their peculiar struc tures. Compared with polyoxometalates, polythiometalate chemistry is still very young. We report here the syntheses, structural characterizations and electrical properties of the novel polythiometalates, {[W3Ag3S12].[La(DMAC) (5)(H2O)(3).(DMAC)(4)]} 1 and {[W8Ag10S32].[M(DEF)(8)](2)}(n) (M=La 2 and M =Nd 3). The complexes were obtained by self-assembly of (NH4)WS4 and AgNO3 with Ln(NO3)(3) (Ln=La, Nd) in different solvents: DMAC (DMAC=N N'-dimethyl acetamide), DEF (DEF=N ,N'-diethylformamide). The title compounds represent two novel structure types of W/Ag/S polythiometalates, 1: a single-strande d helix chain; 2 and 3 are isomorphous: equal step zigzag chains with a dou ble square unit. The unusual 1 has two helices: an anion chain and a cation chain simultaneously exist in the unit cell and the anion helix is defined by a pitch (length per turn) of 17.65 Angstrom, and a radius of circumscri bed cylinder of 8.88 Angstrom. Room temperature conductivities of 1, 2/3 ar e 1.16x10(-4), 2.58x10(-4) S cm(-1).