The composition and structure of lithium tetrakis(pentafluorophenyl)borate diethyletherate

Treatment of LiC6F5 with B(C6F5)3 in equal volumes of light petroleum and diethyl ether at low temperature followed by slow warming to room temperature precipitates a microcrystalline solid which dries under vacuum to a material with the composition [Li(OEt2)3][B(C6F5)4]. Crystallization from diethyl ether yields solvent dependent [Li(OEt2)4][B(C6F5)4], which has been crystallographically characterised.