Caesium hexafluorocuprate is the inorganic compound with the chemical formula Cs2CuF6. It is a red solid that degrades upon contact with water. It was first prepared by heating CsCuCl3 and caesium fluoride at 410 °C under 350 atmospheres of fluorine:2 CsCuCl3 + 2 CsF + 5 F2 → 2 Cs2CuF6 + 3 Cl2