IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

Glass Ball as Bullet Solubility System: Ammonia with Phosphoric acid, Sulfuric acid, Potassium oxide and Water

   (1) Ammonia; NH3; [7664-41-7]  NIST Chemistry WebBook for detail
   (2) Phosphoric acid; H3PO4; [7664-38-2]  NIST Chemistry WebBook for detail
   (3) Potassium oxide; K2O; [12136-45-7]  NIST Chemistry WebBook for detail
   (4) Sulfuric acid; H2SO4; [7664-93-9]  NIST Chemistry WebBook for detail
   (5) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail

   J. Eysseltová; Charles University; Prague, Czech Republic (September 1995)

Critical Evaluation:

Solubilities in the NH3-H3PO4-H2SO4-H2O System

          The quaternary system NH3-H3PO4-H2SO4-H2O may be formed by the addition of H2SO4 to the ternary system NH3-H3PO4-H2O. There are four reports1-4 that contain solubility data for this quaternary system. The solubility data in these four reports agree reasonably well with each other after discounting a systematic error in two of the reports.1,2 Therefore these solubility data are considered to be reliable. Furthermore, the existence of (NH4)2H3PO4SO4 [25993-60-1] is also considered to have been established as well as the fact that it is congruently soluble in water over a temperature range of 273 K to 373 K.
          In two reports5,6 the system is described as NH4H2PO4-(NH4)2HPO4-(NH4)2SO4-H2O. The Evaluator believes that a comparison can be made of the solubility data for this system and that of the system described in the preceding paragraph. Such a comparison can be made at 273 K, 298 K and 323 K. To do this, the isotherms were depicted in tetrahedral coordinates and then projected on planes perpendicular to an edge of the NH3-H3PO4-H2SO4 triangle.15 Such a projection gives absolute solubility values, the shape and position of individual crystallization fields, and any scatter in the reported data. Using this procedure, all the data in Refs. 1-4,6 are in satisfactory agreement with each other. The data reported by Kaganskiy and Babenko5 and by Uno3 agree with each other but there is significant scatter in the data near the crystallization surface.
          Fokina et al.,7 studied the NH4H2PO4-H3PO4-K2SO4-H2O system. Such a system can be considered as a section through the NH3-H3PO4-H2SO4-K2O-H2O system where the molar ratio H2SO4/K2O = 1. Solid solutions between ammonium and potassium dihydrogenphosphates exist as solid equilibrium phases in this system. The ability of these two dihydrogenphosphates to form such solid solutions (designated as β-solid solution) has been proved in studies of the NH4H2PO4-KH2PO4-H2O system.8-14

Experimental Data:   (Notes on the Nomenclature)

References: (Click a link to see its experimental data associated with the reference)

   1  Berlin, L.E.; Mantsev, B.M., Zh. Prikl. Khim. (Leningrad) 1933, 6, 385.; Vol'fkovich, S.I.; Berlin, L.E.; Mantsev, B.M., Tr. NIUIFa 1940, 228.
   2  Vol'fkovich, S.I.; Berlin, L.E.; Mantsev, B.M., Tr. NIUIFa 1940, 228.
   3  Uno, S., Kogyo Kagaku Zashi 1940, 43, 399; J. Soc. Chim. Ind., Japan, Suppl. Binding 1940, 43, 168B/70B.
   4  Mishchenko, Yu.S.; Chepelevetskiy, M.L., Tr. NIUIFa 1965, 208, 30.
   5  Kaganskiy, I.M.; Babenko, A.M., Zh. Prikl. Khim. (Leningrad) 1975, 48, 1387.
   6  Akiyama, T.; Kanzaki, H.; Minagawa, S., Nippon Dojo Hiryogaku Zasshi 49, 243 (1978).
   7  Fokina, Z.N.; Kornishina, E.N.; Kim, P.P., Tekhnologiya Mineral'nykh Udobreniy (Leningrad) 63 (1977).
   8  Askenasy, P.; Nessler, F., F.Z. Anorg. Chem. 189, 305 (1930).
   9  Dombrovskaya, N.S.; Zvorykin, A.Ya., Kaliy 1937, 2, 24.
   10  Zvorykin, A.Y.; Kuznetsov, V.G., Izv. AN SSSR, Ser. Khim. 1938, 195.
   11  Kuznetsov, D.I.; Kozhukhovskiy, A.A.; Borovaya, F.E., Zh. Prikl. Khim. (Leningrad) 21, 1278 (1948).
   12  Bergman, A.G.; Gladkovskaya, A.A.; Galushkina, R.A., Zh. Neorg. Khim. 1972, 17, 3368.
   13  Shenkin, Ya.S.; Ruchnova, S.A.; Rodionova, N.A., Zh. Neorg. Khim. 1972, 17, 3368.
   14  Solov'ev, A.P.; Balashova, E.F.; Verendykina, N.A.; Zyuzina, L.F., Vzaimodeistvie Khloridov Kaliya, Magniya, Ammoniya s ikh Nitratami i Fosfatami 1977, 3.
   15  Eysseltová, J., to be published.