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:
   Kaganskiy, I.M.; Babenko, A.M., Zh. Prikl. Khim. (Leningrad) 1971, 44, 315.

Variables:

   Concentration = Temperature and composition

Prepared By:
   J. Eysseltová

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

Part 1. Solubility isotherms in the NH₄H₂PO₄-(NH₄)₂HPO₄-H₂O system.
t/°C	Chemical₁	10² * Mass Fraction w₁	Chemical₂	10² * Mass Fraction w₂	Chemical₃	10² * Mass Fraction w₃	m₃ [mol/kg]	Chemical₄	10² * Mass Fraction w₄	m₄ [mol/kg]	Chemical₅	10² * Mass Fraction w₅
0	NH4H2PO4	18.2	(NH4)2HPO4	0.0	NH3 (a)	2.7	1.9	H3PO4 (a)	15.5	1.9	H2O (a)	81.8
0	NH4H2PO4	19.0	(NH4)2HPO4	8.1	NH3 (a)	4.9	3.9	H3PO4 (a)	22.2	3.1	H2O (a)	72.9
0	NH4H2PO4	19.5	(NH4)2HPO4	16.1	NH3 (a)	7.0	6.4	H3PO4 (a)	28.6	4.5	H2O (a)	64.4
0	NH4H2PO4	19.9	(NH4)2HPO4	20.0	NH3 (a)	8.1	7.9	H3PO4 (a)	31.8	5.4	H2O (a)	60.1
0	NH4H2PO4	9.8	(NH4)2HPO4	27.0	NH3 (a)	8.4	7.8	H3PO4 (a)	28.4	4.6	H2O (a)	63.2
0	NH4H2PO4	19.5	(NH4)2HPO4	24.1	NH3 (a)	9.1	9.5	H3PO4 (a)	34.5	6.2	H2O (a)	56.4
0	NH4H2PO4	13.2	(NH4)2HPO4	28.5	NH3 (a)	9.3	9.4	H3PO4 (a)	32.4	5.7	H2O (a)	58.3
0	NH4H2PO4	20.1	(NH4)2HPO4	26.3	NH3 (a)	9.8	10.7	H3PO4 (a)	36.6	7.0	H2O (a)	53.6
0	NH4H2PO4	19.1	(NH4)2HPO4	28.3	NH3 (a)	10.1	11.3	H3PO4 (a)	37.3	7.2	H2O (a)	52.6
0	NH4H2PO4	19.9	(NH4)2HPO4	28.0	NH3 (a)	10.2	11.5	H3PO4 (a)	37.7	7.4	H2O (a)	52.1
0	NH4H2PO4	0.0	(NH4)2HPO4	27.8	NH3 (a)	7.2	5.8	H3PO4 (a)	20.6	2.9	H2O (a)	72.2
0	NH4H2PO4	7.2	(NH4)2HPO4	27.6	NH3 (a)	8.2	7.4	H3PO4 (a)	26.6	4.2	H2O (a)	65.2
0	NH4H2PO4	14.3	(NH4)2HPO4	28.2	NH3 (a)	9.4	9.6	H3PO4 (a)	33.1	5.9	H2O (a)	57.5
0	NH4H2PO4	20.0	(NH4)2HPO4	19.9	NH3 (a)	8.1	7.9	H3PO4 (a)	31.8	5.4	H2O (a)	60.1
0	NH4H2PO4	18.0	(NH4)2HPO4	28.0	NH3 (a)	9.9	10.7	H3PO4 (a)	36.1	6.8	H2O (a)	54.0
0	NH4H2PO4	18.1	(NH4)2HPO4	9.2	NH3 (a)	5.1	4.1	H3PO4 (a)	22.2	3.1	H2O (a)	72.7
-5	NH4H2PO4	6.7	(NH4)2HPO4	23.3	NH3 (a)	7.0	5.9	H3PO4 (a)	23.0	3.4	H2O (a)	70.0
-5	NH4H2PO4	11.2	(NH4)2HPO4	17.8	NH3 (a)	6.2	5.2	H3PO4 (a)	22.7	3.3	H2O (a)	71.0
-5	NH4H2PO4	16.5	(NH4)2HPO4	8.3	NH3 (a)	4.6	3.6	H3PO4 (a)	20.2	2.7	H2O (a)	75.2
-5	NH4H2PO4	18.1	(NH4)2HPO4	8.2	NH3 (a)	4.8	3.8	H3PO4 (a)	21.5	3.0	H2O (a)	73.7
-5	NH4H2PO4	18.3	(NH4)2HPO4	16.3	NH3 (a)	6.9	6.2	H3PO4 (a)	27.7	4.3	H2O (a)	65.4
-5	NH4H2PO4	18.7	(NH4)2HPO4	20.3	NH3 (a)	8.0	7.7	H3PO4 (a)	31.0	5.2	H2O (a)	61.0
-5	NH4H2PO4	18.4	(NH4)2HPO4	24.5	NH3 (a)	9.0	9.3	H3PO4 (a)	33.9	6.0	H2O (a)	57.1
-5	NH4H2PO4	18.7	(NH4)2HPO4	26.8	NH3 (a)	9.7	10.4	H3PO4 (a)	35.8	6.7	H2O (a)	54.5
-5	NH4H2PO4	17.7	(NH4)2HPO4	11.7	NH3 (a)	5.6	4.7	H3PO4 (a)	23.8	3.4	H2O (a)	70.6
-5	NH4H2PO4	8.3	(NH4)2HPO4	17.5	NH3 (a)	5.7	4.5	H3PO4 (a)	20.1	2.8	H2O (a)	74.2
-5	NH4H2PO4	0.0	(NH4)2HPO4	24.3	NH3 (a)	6.3	4.9	H3PO4 (a)	28.0	2.4	H2O (a)	75.7
-5	NH4H2PO4	18.8	(NH4)2HPO4	24.8	NH3 (a)	9.2	9.6	H3PO4 (a)	34.4	6.2	H2O (a)	56.4
-5	NH4H2PO4	7.5	(NH4)2HPO4	25.5	NH3 (a)	7.7	6.7	H3PO4 (a)	25.3	3.9	H2O (a)	67.0
-5	NH4H2PO4	14.9	(NH4)2HPO4	25.7	NH3 (a)	8.8	8.7	H3PO4 (a)	31.8	5.5	H2O (a)	59.4
-5	NH4H2PO4	18.4	(NH4)2HPO4	26.4	NH3 (a)	9.5	10.1	H3PO4 (a)	35.3	6.5	H2O (a)	55.2
-5	NH4H2PO4	0.0	(NH4)2HPO4	26.4	NH3 (a)	6.8	5.4	H3PO4 (a)	19.6	2.7	H2O (a)	73.6
10	NH4H2PO4	20.6	(NH4)2HPO4	0.0	NH3 (a)	3.0	2.3	H3PO4 (a)	17.5	2.3	H2O (a)	79.4
10	NH4H2PO4	21.8	(NH4)2HPO4	7.8	NH3 (a)	5.2	4.4	H3PO4 (a)	24.4	3.5	H2O (a)	70.4
10	NH4H2PO4	22.2	(NH4)2HPO4	15.5	NH3 (a)	7.3	6.9	H3PO4 (a)	30.4	5.0	H2O (a)	62.3
10	NH4H2PO4	22.4	(NH4)2HPO4	19.4	NH3 (a)	8.3	8.4	H3PO4 (a)	33.5	5.9	H2O (a)	58.2
10	NH4H2PO4	21.9	(NH4)2HPO4	23.4	NH3 (a)	9.3	10.0	H3PO4 (a)	36.0	6.7	H2O (a)	54.7
10	NH4H2PO4	22.7	(NH4)2HPO4	25.5	NH3 (a)	9.9	11.3	H3PO4 (a)	38.3	7.5	H2O (a)	51.8
10	NH4H2PO4	22.4	(NH4)2HPO4	27.1	NH3 (a)	10.3	12.0	H3PO4 (a)	39.2	7.9	H2O (a)	50.5
10	NH4H2PO4	17.0	(NH4)2HPO4	33.2	NH3 (a)	11.1	13.1	H3PO4 (a)	39.1	8.0	H2O (a)	49.8
10	NH4H2PO4	21.8	(NH4)2HPO4	31.2	NH3 (a)	11.3	14.1	H3PO4 (a)	41.7	9.1	H2O (a)	47.0
10	NH4H2PO4	0.0	(NH4)2HPO4	33.1	NH3 (a)	8.5	7.5	H3PO4 (a)	24.6	3.7	H2O (a)	66.9
10	NH4H2PO4	6.6	(NH4)2HPO4	33.6	NH3 (a)	9.6	9.5	H3PO4 (a)	30.6	5.2	H2O (a)	59.8
10	NH4H2PO4	13.2	(NH4)2HPO4	33.8	NH3 (a)	10.7	11.8	H3PO4 (a)	36.3	7.0	H2O (a)	53.0
10	NH4H2PO4	22.4	(NH4)2HPO4	10.2	NH3 (a)	5.9	5.2	H3PO4 (a)	26.7	4.0	H2O (a)	67.4
10	NH4H2PO4	16.8	(NH4)2HPO4	32.5	NH3 (a)	10.9	12.6	H3PO4 (a)	38.4	7.7	H2O (a)	50.7
10	NH4H2PO4	22.8	(NH4)2HPO4	24.0	NH3 (a)	9.6	10.6	H3PO4 (a)	37.2	7.1	H2O (a)	53.2
10	NH4H2PO4	20.3	(NH4)2HPO4	32.3	NH3 (a)	11.3	14.0	H3PO4 (a)	41.3	8.9	H2O (a)	47.4

Part 2. Crystallization temperatures and composition of solutions existing in equilibrium with two or three solid phases.
t/°C	Chemical₁	10² * Mass Fraction w₁	Chemical₂	10² * Mass Fraction w₂	Chemical₃	10² * Mass Fraction w₃	m₃ [mol/kg]	Chemical₄	10² * Mass Fraction w₄	m₄ [mol/kg]	Chemical₅	10² * Mass Fraction w₅	Solid Phase(s)^(b)
-4.4	NH4H2PO4	17.50	(NH4)2HPO4	0.00	NH3 (a)	2.59	1.84	H3PO4 (a)	14.91	1.84	H2O (a)	82.50	A + B
-5.3	NH4H2PO4	18.00	(NH4)2HPO4	8.20	NH3 (a)	4.78	3.80	H3PO4 (a)	21.42	2.96	H2O (a)	73.80	A + B
-6.4	NH4H2PO4	18.00	(NH4)2HPO4	16.40	NH3 (a)	6.89	6.17	H3PO4 (a)	27.50	4.28	H2O (a)	65.60	A + B
-7.4	NH4H2PO4	18.00	(NH4)2HPO4	20.50	NH3 (a)	7.95	7.59	H3PO4 (a)	30.55	5.07	H2O (a)	61.50	A + B
-5.4	NH4H2PO4	17.60	(NH4)2HPO4	12.00	NH3 (a)	5.70	4.75	H3PO4 (a)	23.90	3.46	H2O (a)	70.40	A + B
-5.1	NH4H2PO4	18.70	(NH4)2HPO4	26.80	NH3 (a)	9.68	10.43	H3PO4 (a)	35.82	6.71	H2O (a)	54.50	B + C
-0.3	NH4H2PO4	19.80	(NH4)2HPO4	28.00	NH3 (a)	10.15	11.42	H3PO4 (a)	37.64	7.36	H2O (a)	52.20	B + C
-6.0	NH4H2PO4	18.50	(NH4)2HPO4	26.00	NH3 (a)	9.44	9.99	H3PO4 (a)	35.05	6.44	H2O (a)	55.50	B + C
+6.8	NH4H2PO4	21.30	(NH4)2HPO4	31.40	NH3 (a)	11.25	13.97	H3PO4 (a)	41.44	8.94	H2O (a)	47.30	B + D
+18.8	NH4H2PO4	23.60	(NH4)2HPO4	32.50	NH3 (a)	11.88	15.88	H3PO4 (a)	44.22	10.28	H2O (a)	43.90	B + D
-5.4	NH4H2PO4	0.00	(NH4)2HPO4	6.30	NH3 (a)	6.78	5.40	H3PO4 (a)	19.52	2.70	H2O (a)	73.70	A + C
-6.6	NH4H2PO4	7.50	(NH4)2HPO4	25.00	NH3 (a)	7.56	6.57	H3PO4 (a)	24.94	3.77	H2O (a)	67.50	A + C
-8.2	NH4H2PO4	15.10	(NH4)2HPO4	24.40	NH3 (a)	8.53	8.28	H3PO4 (a)	30.97	5.22	H2O (a)	60.50	A + C
+16.0	NH4H2PO4	0.00	(NH4)2HPO4	39.60	NH3 (a)	10.21	9.93	H3PO4 (a)	29.38	4.96	H2O (a)	60.40	C + D
+12.0	NH4H2PO4	6.48	(NH4)2HPO4	35.20	NH3 (a)	10.04	10.11	H3PO4 (a)	31.64	5.54	H2O (a)	58.32	C + D
+9.4	NH4H2PO4	13.20	(NH4)2HPO4	33.70	NH3 (a)	10.65	11.77	H3PO4 (a)	36.25	6.97	H2O (a)	53.10	C + D
+8.6	NH4H2PO4	16.90	(NH4)2HPO4	32.20	NH3 (a)	10.81	12.47	H3PO4 (a)	38.29	7.68	H2O (a)	50.90	C + D
-8.6	NH4H2PO4	17.80	(NH4)2HPO4	24.66	NH3 (a)	8.99	9.18	H3PO4 (a)	33.46	5.93	H2O (a)	57.54	A + B + C
+3.4	NH4H2PO4	21.20	(NH4)2HPO4	31.60	NH3 (a)	11.29	14.04	H3PO4 (a)	41.51	8.97	H2O (a)	47.20	B + C + D

Notes:
   Table 2  ^a  These values were calculated by the compiler.
   Table 2  ^b  Solid phases are: A=ice; B=NH₄H₂PO₄; C=(NH₄)₂HPO₄·2H₂O; D=(NH₄)₂HPO₄.

Method/Apparatus/Procedure:
   A modified polythermic method was used.¹

Source and Purity of Materials:
   Chemically pure or reagent grade salts were used. They were recrystallized twice. During the recrystallization special care was taken to obtain anhydrous (NH₄)₂HPO₄. The products were dried gently at 30 °C to 50 °C and analyzed for NH₃ and P₂O₅ content.

Estimated Errors:
   Solubility: No information is given.
   Temperature: No information is given.

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