Potassium trans‐diaqua­bis[oxalato(2–)‐κ2O,O′]chromate(III)

The title compound, K[Cr(C2O4)2(H2O)2], was crystallized from an aqueous solution. It is the first member without uncoordinated water molecules of formula Am[M(C2O4)2(H2O)2]·xH2O, where A = monovalent cation, m = 1 or 2, M = metal(II) or metal(III), x ≥ 0. The crystal packing is governed by electrostatic and coordinative inter­actions, and inter­molecular hydrogen bonds help to stabilize the packing. The coordination of the Cr sites is quasi-octa­hedral, and the K ions are eight-coordinated by O atoms of oxalate ligands, forming strongly distorted square anti­prisms.