Abstract: The present invention is directed to a family of trimetallic nitride endohedral metalloheterofullerenes having the formula Ax X3-x N@Cn N, (x=0, 1, 2 or 3) (n=number of carbon atoms in the cage, typically between 59 and 199), wherein A and X are metal atoms encased within the cage, C is carbon and N is nitrogen. A and X are preferably selected from rare earth elements or group IIIB elements. A or X metal atoms are scandium, yttrium, lanthanum, gadolinium, lutetium, holmium, erbium, thulium, dysprosium, neodymium, cerium, praseodymium and ytterbium. Representative embodiments include Sc3N@C79N, Y3N@C79N, La3N@C79N, Tb3N@C79N, Ho3N@C79N, LaSc2N@C79N, PrSc2N@C79N, GdSc2N@C79N, La2ScN@C79N, and Gd2ScN@C79N. The present invention is also directed to a method of making the inventive endohedral metalloheterofullerenes having the formula AxX3-xN@CnN. These methods involve use of oxidizing gases (e.g.

Abstract: The present invention is directed to a family of endohedral metalloheterofullerenes representative generally as AX@C79N where A and X metal atoms. A and X may be lanthanide metals or rare earth metals. In some embodiments, A and X may be Yttrium, Scandium, Terbium, Lanthanum, Gadolinium, Holmium, Erbium, Thulium, or Ytterbium. A and X may be the same type of metal atom or they may be different. The endohedral metalloheterofullerenes are neutral compounds that can be readily isolated using standard chromatographic techniques. The endohedral metalloheterofullerenes exhibit parmagnetic properties.