The title compound, pentatantalum tetraantimonide, was obtained as a by-product of the reaction between Ba and Sb mixed in a 1:2 molar ratio using tantalum as a reaction container. This compound adopts the Ti5Te4 structure type, which consists of chains of vertexsharing Ta6Sb8 face-capped octahedral clusters. The resulting formulation is Ta4Ta2/2Sb8/2. Distance ranges are: Ta--Ta 2.930(1)-3.301 (1) and Ta--Sb 2.775 (2)- 3.074 (1) A,; there are no bonding Sb..-Sb distances. Closer inspection reveals that the Ta substructure also resembles chains cut out from bcc packing.