IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

Glass Ball as Bullet Solubility System: Ammonium dihydrogenphosphate with Ammonium nitrate, Potassium dihydrogenphosphate, Potassium nitrate and Water

   (1) Ammonium dihydrogenphosphate; NH4H2PO4; [7722-76-1]  NIST Chemistry WebBook for detail
   (2) Ammonium nitrate; NH4NO3; [6484-52-2]  NIST Chemistry WebBook for detail
   (3) Potassium dihydrogenphosphate; KH2PO4; [7778-77-0]  NIST Chemistry WebBook for detail
   (4) Potassium nitrate; KNO3; [7757-79-1]  NIST Chemistry WebBook for detail
   (5) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail

Original Measurements:
   Bergman, A.G.; Opredelenkova, L.V.; Dzuev, A.B., Ukr. Khim. Zh. 33, 285 (1967).


   Concentration = Temperature and composition.

Prepared By:
   J. Eysseltová

Experimental Data:   (Notes on the Nomenclature)
(Please see footnotes following the table(s).)
Crystallization temperature and composition of invariant points in the KNO3-NH4H2PO4-H2O system.
t/°CChemical1102 * Mass Fraction w1m1 [mol/kg](a)Chemical2102 * Mass Fraction w2m2 [mol/kg](a)Chemical3102 * Mass Fraction w3Solid Phase(s)(b)
-7.7KNO38.51.1NH4H2PO415.51.77H2O76.0A + B + C
5.5KNO316.02.33NH4H2PO416.02.05H2O68.0B + C + D
40KNO335.06.53NH4H2PO412.01.97H2O53.0B + D + E
16.5KNO311.51.85NH4H2PO427.03.82H2O61.5C + D + F
92.5KNO316.04.52NH4H2PO449.012.2H2O35.0D + E + F
   Table 1  a  These values were calculated by the compiler.
   Table 1  b  The solid phases are: A=ice; B=α-KNO3; C=α-NH4H2PO4; D="unidentified conversion product":; E=β-KNO3; F=β-NH4H2PO4.

   A polythermic method was used.1 The appearance of the first crystals as well as the disappearance of the last crystals was recorded.

Source and Purity of Materials:
   Reagent grade KNO3 and NH4H2PO4 were recrystallized and dried before being used. Their melting points were 337 °C and 200 °C, respectively.

Estimated Errors:
   Solubility: No information given.
   Temperature: The only information given is that the difference between the temperature of dissolution of the last crystal and appearance of the first crystal was kept to a minimum.

   1A. G. Bergman and N. P. Luzhnaya, Fiziko-Khimicheskie Osnovy Izucheniya i Ispol'zovaniya Solyanykh Mestorozhdeniy Khlorid-Sul'fatnogo Tipa, Moscow, IAN SSSR (1951).