The title compound was obtained as a by-product when elemental Ba [rod, Aesar (99.99%)], Au [powder, 100 mesh, Aesar (99.999%)], and Sb [powder, 100 mesh, Aesar (99.999%)] were loaded into a tantalum tube (Nobel-Met. Ltd, >99.85%, 0.375 OD) in a 1:1:2 molar ratio in an Ar-filled glove-box. The tube was sealed in an arc-melter under argon, and heated to 973 K for 3 d in a fused-silica jacket. The reaction container was cooled slowly to 673 K at 10 K h⁻¹, and then quenched to room temperature. When the tantalum tube was opened in the Ar-filled glove-box, gray irregular-shaped crystals of the title compound were found in the product. Suitable single crystals were mounted in 0.3 mm thin-walled capillaries for subsequent diffraction experiments.