Dipotassium aqua­penta­fluoro­vanadate

The title compound, K₂VF₅(H₂O)], was synthesized from potassium antimony tartrate, piperazine, V₂O₅ and HF under hydro­thermal conditions. It is isostructural with K₂FeF₅(H₂O)] and contains polymeric anion chains held together by strong O—H?F bonds. Each V atom is coordinated to five terminal F atoms and the O atom of one water mol­ecule. Pairs of O—H?F bonds are formed by two cis‐related F atoms. Twofold axes run along the O—V—F axis of the V‐centred otahedra.