Disproportionation of Rb3C60 by ammonia to produce two new ammoniated fullerides

Intercalation of ammonia into the superconductor Rb3C60 results in the short term in the formation of a material best described as quasicrystalline or icosahedrally coordinated glass. When allowed to age and equilibrate, this material disproportionates to a mixture of orthorhombic RbC60 and two new phases whose structures we have determined by combined X-ray and neutron powder diffraction. They are a cubic Fm-3m phase, Rb3CF60(ND3)4.8, and a body-centred orthorhombic Immm phase of composition Rb4C60(ND3)1.7.