Factors affecting the solubility of ammonium acid urate.

Evidence is presented that sodium acid urate exists in aqueous solution in a non-colloidal state. The levels of ammonium and urate ions required to precipitate ammonium acid urate have been established for some aqueous media. The effect of pH on the formation product of ammonium acid urate is described. Evidence is presented that there is no epitaxial relationship between this salt and calcium oxalate monohydrate.