IUPAC-NIST Solubilities Database

IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

Solubility System: Ammonia with Phosphoric acid and Water

Components:
   (1) Ammonia; NH3; [7664-41-7]  NIST Chemistry WebBook for detail
   (2) Phosphoric acid; H3PO4; [7664-38-2]  NIST Chemistry WebBook for detail
   (3) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail

Original Measurements:
   Vol'fkovich, S.I.; Berlin, L.E.; Mantsev, B.M., Tr. NIUIFa 1940, 228.

Variables:

   Concentration = Composition at 25 ºC.

Prepared By:
   L.V. Chernykh and J. Eysseltová

Experimental Data:   (Notes on the Nomenclature)
(Please see footnotes following the table(s).)

Table I. Solubility in the NH₄H₂PO₄-(NH₄)₂HPO₄-H₂O system at 25 °C.
Chemical₁	Composition₁ [g/100 g H2O]	Chemical₂	Composition₂ [g/100 g H2O]	Chemical₃	10² * Mass Fraction w₃	m₃ [mol/kg]	Chemical₄	10² * Mass Fraction w₄^70.8	m₄ [mol/kg]	Chemical₅	10² * Mass Fraction w₅	Solid Phase(s)^(b)
NH4H2PO4	41.3	(NH4)2HPO4	0.0	NH3 (a)	4.33	3.59	H3PO4 (a)	24.9	3.59	H2O (a)	57.3	A
NH4H2PO4	43.7	(NH4)2HPO4	4.00	NH3 (a)	5.08	4.40	H3PO4 (a)	27.2	4.10	H2O (a)	70.8	A
NH4H2PO4	53.7	(NH4)2HPO4	27.2	NH3 (a)	8.27	8.79	H3PO4 (a)	36.4	6.73	H2O (a)	67.7	A
NH4H2PO4	60.1	(NH4)2HPO4	43.2	NH3 (a)	9.86	11.8	H3PO4 (a)	41.0	8.50	H2O (a)	55.3	A
NH4H2PO4	59.2	(NH4)2HPO4	71.6	NH3 (a)	11.8	16.0	H3PO4 (a)	44.9	10.6	H2O (a)	49.2	A
NH4H2PO4	66.9	(NH4)2HPO4	80.8	NH3 (a)	12.4	18.1	H3PO4 (a)	47.2	11.9	H2O (a)	43.3	A + B
NH4H2PO4	0.0	(NH4)2HPO4	74.5	NH3 (a)	11.0	11.3	H3PO4 (a)	31.7	5.64	H2O (a)	40.4	B

Table II. Solubility in the (NH₄)₂HPO₄-(NH₄)₃PO₄-H₂O system at 25 °C.
Chemical₁	Composition₁ [g/100 g H2O]	Chemical₂	Composition₂ [g/100 g H2O]	Chemical₃	10² * Mass Fraction w₃	m₃ [mol/kg]	Chemical₄	10² * Mass Fraction w₄^57.3	m₄ [mol/kg]	Chemical₅	10² * Mass Fraction w₅	Solid Phase(s)^(b)
(NH4)2HPO4	74.5	(NH4)3PO4	0.0	NH3 (a)	11.0	11.3	H3PO4 (a)	31.7	5.64	H2O (a)	81.0	B
(NH4)2HPO4	64.3	(NH4)3PO4	6.59	NH3 (a)	11.0	11.1	H3PO4 (a)	30.5	5.31	H2O (a)	57.3	B + C
(NH4)2HPO4	52.4	(NH4)3PO4	6.45	NH3 (a)	9.90	9.23	H3PO4 (a)	27.1	4.40	H2O (a)	58.5	C
(NH4)2HPO4	47.5	(NH4)3PO4	6.24	NH3 (a)	9.36	8.45	H3PO4 (a)	25.6	4.02	H2O (a)	63.0	C
(NH4)2HPO4	0.0	(NH4)3PO4	23.4	NH3 (a)	6.50	4.71	H3PO4 (a)	12.5	1.57	H2O (a)	65.0	C

Table III. Solubility in the NH₃-H₃PO₄-H₂O system at 25 °C.
Chemical₁	10² * Mass Fraction w₁	Chemical₂	10² * Mass Fraction w₂	m₂ [mol/kg]^(a)	Chemical₃	10² * Mass Fraction w₃	m₃ [mol/kg]	Chemical₄	10² * Mass Fraction w₄	Solid Phase(s)^(b)
NH3	4.23	P2O5	18.1	3.51	H3PO4 (a)	25.0	3.60	H2O (a)	70.8	A
NH3	5.08	P2O5	19.7	4.40	H3PO4 (a)	27.2	4.10	H2O (a)	67.7	A
NH3	6.53	P2O5	22.8	6.19	H3PO4 (a)	31.5	5.18	H2O (a)	62.0	A
NH3	8.26	P2O5	26.4	8.77	H3PO4 (a)	36.5	6.73	H2O (a)	55.3	A
NH3	9.84	P2O5	29.7	11.8	H3PO4 (a)	41.0	8.51	H2O (a)	49.2	A
NH3	11.8	P2O5	32.6	16.0	H3PO4 (a)	45.0	10.6	H2O (a)	43.2	A
NH3	12.5	P2O5	34.2	18.2	H3PO4 (a)	47.2	12.0	H2O (a)	40.3	A + B
NH3	10.7	P2O5	23.2	11.0	H3PO4 (a)	32.0	5.71	H2O (a)	57.3	B
NH3	10.7	P2O5	21.9	10.6	H3PO4 (a)	30.2	5.22	H2O (a)	59.1	B + C
NH3	9.52	P2O5	19.2	8.74	H3PO4 (a)	26.5	4.23	H2O (a)	64.0	C
NH3	8.98	P2O5	18.4	8.04	H3PO4 (a)	25.4	3.95	H2O (a)	65.6	C
NH3	4.79	P2O5	6.66	3.27	H3PO4 (a)	9.20	1.09	H2O (a)	86.0	C
NH3	6.70	P2O5	2.29	4.36	H3PO4 (a)	3.16	0.358	H2O (a)	90.1	C

Notes:
   Table 3  ^a  These values were calculated by the compilers.
   Table 3  ^b  The solid phases are: A=NH₄H₂PO₄; B=(NH₄)₂HPO₄; C=(NH₄)₃HPO₄·3H₂O.
   Table 3  ^c  These data appear in source paper 2 only. The rest of the data are in both source papers.

Method/Apparatus/Procedure:
   The isothermal method was used. Equilibration required 4 to 5 days. The composition of the solid phases was determined by the Schreinemakers method.

Source and Purity of Materials:
   No information is given.

Estimated Errors:

   Temperature: The temperature was kept constant within 0.05 K.