Using a Porphyrin Diacid Cation to Stabilize a Square-Pyramidal BiX5 (X = Br, Cl/Br) Unit.

Main-group halogenido metalates are a diverse class of compounds with an intricate structural chemistry and a wide range of applications. Here, we present an unprecedented anion motif in the structural chemistry of halogenido bismuthates, a square-pyramidal BiX5 unit. We show how the porphyrin diacid used as our compounds' counterion is templating the formation of this new motif, suggesting that other strong anion receptors may be able to stabilize unique metalate anions in future work.