hydrogen, NR3 R4 or NR5, with at lest one of R1 and R2 being other than hydrogen, R3 and R4 are independently chosen from hydrogen or a monovalent organic radical, and R5 is a divalent organic radical, the molar ratio of the chalcogen-containing compound to the acid is about 1 or more, the molar ratio of water to the combination of acid and chalcogen-containing compound is about 20 or less.