The invention is directed to a method for producing metal-containing particles, the method comprising subjecting an aqueous solution comprising a metal salt, Eh, lowering reducing agent, pH adjusting agent, and water to conditions that maintain the Eh value of the solution within the bounds of an Eh-pH stability field corresponding to the composition of the metal-containing particles to be produced, and producing said metal-containing particles in said aqueous solution at a selected Eh value within the bounds of said Eh-pH stability field. The invention is also directed to the resulting metal-containing particles as well as devices in which they are incorporated.