Superconducting properties of new heterofullerides synthesized for the first time AnMmHgxC60 (A = K, Rb, Cs; M = Be, Mg, B, Al, Ga, In; n = 1, 2; m = 1, 2; x ≪ 1) were investigated at low temperatures. The low frequency inductive method was used to detect a superconducting transition. All the samples were studied by X-ray diffraction (XRD), solid state nuclear magnetic resonance (NMR), electron spin resonance (ESR), and Raman scattering. It is found that most of the superconducting heterofullerides are potassium heterofullerides. For the fulleride K2GaHgxC60 the critical temperature of the superconducting transition is Tc = 20 K. Indium and boron heterofullerides are not superconductors. The synthesis of heterofullerides via amalgams (Hg–K–Mg, Hg–Rb–Al) gives rise to two different superconducting phases.

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