IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

Glass Ball as Bullet Solubility System: Ammonium dihydrogenphosphate with Diammonium hydrogenphosphate, Ammonium nitrate, Potassium sulfate 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) Diammonium hydrogenphosphate; (NH4)2HPO4; [7783-28-0]  NIST Chemistry WebBook for detail
   (4) Potassium sulfate; K2SO4; [7778-80-5]  NIST Chemistry WebBook for detail
   (5) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail

Original Measurements:
   Babenko, A.M.; Andrianov, A.M., Zh. Prikl. Khim. (Leningrad) 57, 1921-5 (1984).


   Concentration = Temperature and concentration of NH4NO3 and K2SO4 in a mixture containing a mol ratio of NH4H2PO4/(NH4)2HPO4 = 1.

Prepared By:
   J. Eysseltová

Experimental Data:   (Notes on the Nomenclature)
(Please see footnotes following the table(s).)
Part 1. Points of simultaneous crystallization of two or three solid phases in the NH4H2PO4-(NH4)2HPO4-NH4NO3-K2SO4-H2O system
t/°CChemical1102 * Mass Fraction w1(b)m1 [mol/kg](b)Chemical2102 * Mass Fraction w2(b)Chemical3102 * Mass Fraction w3(b)Chemical4102 * Mass Fraction w4(b)m4 [mol/kg](b)Chemical5102 * Mass Fraction w5(b)m5 [mol/kg](b)Chemical6102 * Mass Fraction w6(b)Solid Phase(s)(c)
-7.5mixture8.50.5NH4H2PO44.0(NH4)2HPO44.5NH4NO39.91.7K2SO48.00.6H2O73.6A + B
-11.0mixture13.20.8NH4H2PO46.1(NH4)2HPO47.1NH4NO315.22.9K2SO45.00.4H2O66.6A + B
-6.0mixture17.71.3NH4H2PO48.2(NH4)2HPO49.5NH4NO320.34.4K2SO45.00.5H2O57.0B + C
14.0mixture19.21.5NH4H2PO48.9(NH4)2HPO410.3NH4NO322.15.4K2SO48.00.9H2O50.7B + C
26.5mixture (a)20.71.9NH4H2PO49.6(NH4)2HPO411.1NH4NO323.86.7K2SO411.01.4H2O44.5B + C
-11.8mixture16.71.1NH4H2PO47.8(NH4)2HPO48.9NH4NO319.33.8K2SO40.00.0H2O64.0A + B + C
9.0mixture8.00.5NH4H2PO43.7(NH4)2HPO44.3NH4NO39.31.7K2SO413.01.1H2O69.7B + D
14.5mixture12.20.8NH4H2PO45.7(NH4)2HPO46.5NH4NO314.02.9K2SO412.61.2H2O61.2B + D
20.0mixture16.31.3NH4H2PO47.6(NH4)2HPO48.7NH4NO318.74.4K2SO412.51.4H2O52.5B + D
25.0mixture18.41.6NH4H2PO48.6(NH4)2HPO49.8NH4NO321.25.5K2SO412.51.5H2O47.9B + D
29.0mixture20.41.9NH4H2PO49.5(NH4)2HPO410.9NH4NO323.66.7K2SO412.01.6H2O44.0B + C + D
-1.6mixture0.00.0NH4H2PO40.0(NH4)2HPO40.0NH4NO30.00.0K2SO46.50.4H2O93.5A + D
Part 2. Solubility isotherms in the NH4H2PO4-(NH4)2HPO4-NH4NO3-K2SO4-H2O system.
t/°CChemical1Mass Fraction w1(c)Chemical2Mass Fraction w2(c)m2(c)Chemical3Mass Fraction w3(c)Chemical4Mass Fraction w4(c)Chemical5Mass Fraction w5(c)m5(c)Chemical6Mass Fraction w6(c)m6(c)Chemical7m7(c)
-5S (a)19.0mixture (b)8.50.5NH4H2PO44.0(NH4)2HPO44.5NH4NO39.81.7K2SO48.60.7H2O73.1
-5S (a)21.5mixture (b)13.10.8NH4H2PO46.1(NH4)2HPO47.0NH4NO315.12.9K2SO46.00.5H2O65.8
-5S (a)20.4mixture (b)17.91.2NH4H2PO48.3(NH4)2HPO49.6NH4NO320.64.2K2SO40.00.0H2O61.5
-5S (a)25.8mixture (b)17.61.3NH4H2PO48.2(NH4)2HPO49.4NH4NO320.34.5K2SO45.20.5H2O56.9
0S (a)20.4mixture (b)8.40.5NH4H2PO43.9(NH4)2HPO44.5NH4NO39.61.7K2SO410.00.8H2O72.0
0S (a)21.2mixture (b)18.61.3NH4H2PO48.7(NH4)2HPO49.9NH4NO321.44.5K2SO40.00.0H2O60.0
0S (a)22.6mixture (b)12.90.8NH4H2PO46.0(NH4)2HPO46.9NH4NO314.92.9K2SO47.30.6H2O64.9
0S (a)26.5mixture (b)17.41.2NH4H2PO48.1(NH4)2HPO49.3NH4NO320.24.5K2SO46.00.6H2O56.4
10S (a)25.6mixture (b)12.50.8NH4H2PO45.8(NH4)2HPO46.7NH4NO314.42.9K2SO410.51.0H2O62.6
10S (a)23.1mixture (b)20.21.4NH4H2PO49.4(NH4)2HPO410.8NH4NO323.35.2K2SO40.00.0H2O56.5
10S (a)29.1mixture (b)16.91.3NH4H2PO47.9(NH4)2HPO49.0NH4NO319.54.5K2SO49.00.9H2O54.6
   Table 1  a  "Mixture" is an equimolar mixture of NH4H2PO4 and (NH4)2HPO4.
   Table 1  b  W=100wi, M=mi/mol kg–1. Mass fractions of the ammonium phosphates and all molalities were calculated by the compiler.
   Table 1  c  The solid phases are: A=ice; B=NH4NO3; C=NH4H2PO4; D=K2SO4.
   Table 2  a  S is the total plant nutrient: (N+PO5 + K2O + S)
   Table 2  b  "Mixture" is an equimolar mixture of NH4H2PO4 and (NH4)2HPO4.
   Table 2  c  W=100wi, M=mi/mol kg–1. Mass fractions of the ammonium phosphates and all molalities were calculated by the compiler.

   An improved polythermic method1 was used.

Source and Purity of Materials:
   Chemically pure or reagent grade salts were recrystallized twice and dried at 40 °C to 50 °C. The material designated "mixture" was prepared by mixing equimolar amounts of NH4H2PO4 and (NH4)2HPO4 and homogenizing by grinding in a mortar.

Estimated Errors:

   Temperature: Precision of temperature measurement was ±0.4 K.

   1Erayzer, L.N.; Kaganskiy, I.M. Zavod. Lab. 1967, 1, 119.