A process is provided for synthesizing a lithium, nickel, manganese and oxygen composition, LiwNixMnyOz, where w is from about 0.8 to about 1.2, x is from about 0.3 to about 0.8, y is from about 1.3 to about 1.8, and z is from about 3.8 to about 4.2. The composition has a lattice parameter “a” value and wt % crystalline spinel value within the bounds defined by the following lattice parameter “a” and wt % crystalline spinel coordinate values of about (8.1690 Å, 98.5%), about (8.1765 Å, 98.5%), about (8.1810 Å, 96.2%), about (8.1810 Å, 93.4%), about (8.1771 Å, 93.4%), and about (8.1690 Å, 97.6%).