A benzene-rich pseudopolymorph of bis[mu-1,3-bis(pentafluorophenyl)propane-1,3-dionato]-kappa(3)O,O':O';kappa(3)O:O,O'-bis{aqua[1,3-bis(pentafluorophenyl)propane-1,3-dionato-kappa(2)O,O']nickel(II)} benzene tetrasolvate.