Tris(ethyl­enediamine)cobalt(III) nona­iodo­dibismuthate

The asymmetric unit of the title compound, [Co(C₂H₈N₂)₃][Bi₂I₉], crystallizes in the ortho­rhom­bic space group Cmc2₁. The asymmetric unit contains half of a [Co(en)₃]³⁺ cation (en is ethyl­enediamine) and half of a [Bi₂I₉]^3- anion. Both species are located on mirror planes, requiring the [Co(en)₃]³⁺ cation to be present as a statistically disordered mixture of both enantiomeric forms. Crystals were grown solvothermally from an ethanol-water solvent mixture using rac-[Co(en)₃]I₃ and bis­muth triiodide as starting materials. The compound is a rare example of a mixed-metal halobismuthate material.