Tantalum halide cluster chemistry is dominated by the highly stable octahedral [Ta6X12]n+ clusters (X ) Cl, Br, I) found in reduced binaries with compositions Ta6X14 and Ta6X15 1 and by dinuclear species like TaX4 (also formulated Ta2X6X4/2)2 and the abundant Ta2Cl6L3 complexes and their derivatives.3 Known tantalum chalcogenide halides are limited to one-dimensional compounds of the type (TaQ4)nX (Q ) Se, Te; n ) 1, 2, 4; X ) Br, I)4 and to the structurally uncharacterized solids TaSCl3 and TaS2Cl2.5