A process of preparing an actinide compound of the formula An.sub.x Z.sub.y wherein An is an actinide metal atom selected from the group consisting of thorium, uranium, plutonium, neptunium, and americium, x is selected from the group consisting of one, two or three, z is a main group element atom selected from the group consisting of nitrogen, phosphorus, oxygen and sulfur, and y is selected from the group consisting of one, two, three or four, comprising:
- admixing an actinide organometallic precursor capable of reacting with a protic Lewis base selected from the group consisting of ammonia, phosphine, hydrogen sulfide and water, wherein said actinide is selected from the group consisting of thorium, uranium, plutonium, neptunium, and americium, a non-polar, non-coordinating solvent, and a protic Lewis base selected from the group consisting of ammonia, phosphine, hydrogen sulfide and water, at temperatures and for time sufficient to form a reaction product of said actinide organometallic precursor and said protic Lewis base;
- heating said reaction product at temperatures and for time sufficient to form the actinide compound.