IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

Glass Ball as Bullet Solubility System: Diammonium hydrogenphosphate with Urea and Water
Components:
   (1) Diammonium hydrogenphosphate; (NH4)2HPO4; [7783-28-0]  NIST Chemistry WebBook for detail
   (2) Urea; CH4N2O; [57-13-6]  NIST Chemistry WebBook for detail
   (3) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail
Evaluator:
   J. Eysseltová; Charles University; Prague, Czech Republic (September 1995)

 Critical Evaluation:
   
9.1. (NH4)2HPO4 - Urea - H2O

          Two investigations of the composition and temperature of the invariant points in this system are available.1,2 But these two sets of data do not agree with each other even with respect to the nature of the equilibrium solid phase. The modifications of urea are the main source of the uncertainty. The evaluation of this question, however, is beyond the scope of this volume. The closely related system (NH4)2HPO4-CO(NH2)2HNO3-H2O was studied by Nabiev et al.3



Experimental Data:   (Notes on the Nomenclature)

References: (Click a link to see its experimental data associated with the reference)
   1  Treshchov, A.G., Dokl. Timiryazevsk. S.-kh. Akad. 29, 402 (1957).
   2  Vereshchagina, V.I.; Endovitskaya, M.P., Zh. Neorg. Khim. 15, 2818 (1970).
   3  Nabiev, M.N.; Tukhtaev, S., Narkhodzaev, A.Kh., and Yunusov, D.Kh., Zh. Neorg. Khim. 21, 3152 (1976).