Stabilising small clusters: synthesis and characterisation of thermolabile [Gd4F7(15-crown-5)4][AsF6]5·6SO2

Addition of 15-crown-5 to [GdF(AsF6)2], both dissolved in liquid SO2, and crystallisation at −30 °C has led to the isolation of the tetranuclear ionic complex [Gd4F7(15-crown-5)4][AsF6]5·6SO2 which is stable up to −10 °C where SO2 loss leads to loss of crystallinity.