IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

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 Solubility System: Ammonium dihydrogenphosphate with Ammonium nitrate, Potassium dihydrogenphosphate, Potassium nitrate and Water

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Components:
   (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:
   Bochkarev, P.F., Tr. Vostoch.-Sibir. Gosud. Inst. 3 (1935); Bergman, A.G.; Bochkarev, P.F., Zh. Prikl. Khim. (Leningrad) 10, 1531 (1937); Bergman, A.G.; Bochkarev, P.F., Izv. Akad. Nauk SSSR, Otd. Mat. Estestv. Nauk 237 (1938).

Variables:

   Concentration = Temperature and composition.

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

Experimental Remarks:

   Remarks: NOTE: The above data are given in both source papers, but source paper (2) also contains data for the composition of solutions in equilibrium with two or three solid phases. These data are given below.

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

Solubility in the NH₄H₂PO₄-KNO₃-H₂O system.

t/°C	Chemical1	Composition1(a)	102 * Mass Fraction w1	m1 [mol/kg](b)	Chemical2	Composition2(a)	102 * Mass Fraction w2	m2 [mol/kg](b)	Chemical3	Composition3(a)	102 * Mass Fraction w3	Solid Phase(s)(c)
0	NH4H2PO4	100	18.4	2.0	KNO3	0	0.0	0.0	H2O	2832	81.6	A
0	NH4H2PO4	75.1	17.2	1.9	KNO3	24.9	5	0.6	H2O	2170	77.8	A
0	NH4H2PO4	62.3	15.8	1.8	KNO3	37.7	8.4	1.1	H2O	1909	75.8	A
0	NH4H2PO4	49.1	13.7	1.6	KNO3	50.9	11.6	1.5	H2O	1773	74.7	A + B
0	NH4H2PO4	53	11.6	1.3	KNO3	47	11.5	1.5	H2O	1990	76.9	B
0	NH4H2PO4	29.4	5.4	0.6	KNO3	70.6	11.4	1.4	H2O	2892	83.2	B
0	NH4H2PO4	0	0.0	0.0	KNO3	100	11.2	1.2	H2O	4448	88.8	B
10	NH4H2PO4	100	21.3	2.4	KNO3	0	0.0	0.0	H2O	2360	78.7	A
10	NH4H2PO4	78.9	20.4	2.4	KNO3	21.1	4.8	0.6	H2O	1847	74.8	A
10	NH4H2PO4	67.6	19.0	2.3	KNO3	32.4	8.0	1.1	H2O	1658	73.0	A
10	NH4H2PO4	55.2	16.4	2.0	KNO3	44.8	11.7	1.6	H2O	1546	71.9	A
10	NH4H2PO4	50.1	15.3	1.9	KNO3	49.9	13.4	1.9	H2O	1491	71.3	A
10	NH4H2PO4	41.5	13.0	1.6	KNO3	58.5	16.1	2.2	H2O	1445	70.9	A + B
10	NH4H2PO4	37.6	11	1.3	KNO3	62.4	16.0	2.2	H2O	1596	73.0	B
10	NH4H2PO4	21.7	5.1	0.6	KNO3	78.3	16.2	2.0	H2O	2136	78.7	B
10	NH4H2PO4	0	0.0	0.0	KNO3	100	16.6	2.0	H2O	2819	83.4	B
20	NH4H2PO4	100	25.5	3.0	KNO3	0	0.0	0.0	H2O	1866	74.5	A
20	NH4H2PO4	82.6	24.0	2.9	KNO3	17.6	4.5	0.6	H2O	1568	71.5	A
20	NH4H2PO4	80.79	22.5	2.8	KNO3	19.21	7.7	1.1	H2O	1681	69.8	A
20	NH4H2PO4	61.1	20	2.5	KNO3	38.9	11.2	1.6	H2O	1342	68.8	A
20	NH4H2PO4	50.2	17	2.2	KNO3	49.8	14.8	2.1	H2O	1287	68.2	A
20	NH4H2PO4	44	15.2	1.9	KNO3	56.0	17.0	2.5	H2O	1253	67.8	A
20	NH4H2PO4	32.2	11.8	1.5	KNO3	67.8	21.8	3.2	H2O	1159	66.4	A + B
20	NH4H2PO4	29.2	10.2	1.3	KNO3	70.8	21.7	3.2	H2O	1247	68.1	B
20	NH4H2PO4	15.5	4.7	0.6	KNO3	84.5	22.4	3.0	H2O	1542	72.9	B
20	NH4H2PO4	0	0.0	0.0	KNO3	100	23.0	3.0	H2O	1781	77.0	B
30	NH4H2PO4	100	30.2	3.8	KNO3	0	0.0	0.0	H2O	1475	69.8	A
30	NH4H2PO4	84.6	27.5	3.5	KNO3	15.4	4.4	0.6	H2O	1338	68.1	A
30	NH4H2PO4	75.8	26.0	3.4	KNO3	24.2	7.3	1.1	H2O	1242	66.7	A
30	NH4H2PO4	66.5	23.9	3.2	KNO3	33.5	10.6	1.6	H2O	1163	65.5	A
30	NH4H2PO4	51	19.2	2.6	KNO3	49.0	16.2	2.5	H2O	1096	64.6	A
30	NH4H2PO4	39.1	15.4	2.1	KNO3	60.9	21.1	3.3	H2O	1045	63.5	A
30	NH4H2PO4	25.6	10.6	1.5	KNO3	74.4	27.0	4.3	H2O	964	62.4	A + B
30	NH4H2PO4	23.5	9.5	1.3	KNO3	76.5	27.2	4.2	H2O	1000	63.3	B
30	NH4H2PO4	11.5	4.3	0.6	KNO3	88.5	29.0	4.3	H2O	1142	66.7	B
30	NH4H2PO4	0	0.0	0.0	KNO3	100	31.0	4.4	H2O	1249	69.0	B

Composition of solutions existing in equilibrium with two or three solid phases.

t/°C	Chemical1	Composition1(a)	102 * Mass Fraction w1	m1(b)	Chemical2	Composition2(a)	102 * Mass Fraction w2	m2(b)	Chemical3	Composition3(a)	102 * Mass Fraction w3	Solid Phase(s)(c)
-4.4	KNO3	0	0	0	NH4H2PO4	100	17.4	1.83	H2O	3032	82.6	A + B
-5.3	KNO3	27.0	5.0	0.62	NH4H2PO4	73.0	15.4	1.68	H2O	2410	79.6	A + B
-6.0	KNO3	41.5	8.6	1.1	NH4H2PO4	58.5	13.8	1.55	H2O	2101	77.6	A + B
0.4	KNO3	49.7	12.0	1.60	NH4H2PO4	50.3	13.8	1.62	H2O	1726	74.2	B + C
12.6	KNO3	60.9	17.4	2.46	NH4H2PO4	39.1	12.7	1.58	H2O	1373	69.9	B + C
20.7	KNO3	68.2	22.0	3.28	NH4H2PO4	31.8	11.7	1.53	H2O	1152	66.3	B + C
32.7	KNO3	75.8	28.6	4.64	NH4H2PO4	24.2	10.4	1.48	H2O	907	61.0	B + C
-5.7	KNO3	47.8	9.5	1.2	NH4H2PO4	52.2	11.8	1.30	H2O	2223	79.7	A + C
-5.4	KNO3	50.1	9.5	1.2	NH4H2PO4	49.9	10.8	1.18	H2O	2356	78.7	A + C
-4.2	KNO3	67.2	9.7	1.1	NH4H2PO4	32.8	5.4	0.55	H2O	3300	84.9	A + C
-2.5	KNO3	100	9.8	1.1	NH4H2PO4	0	0	0	H2O	5169	90.2	A + C
-6.3	KNO3	45.3	9.6	1.2	NH4H2PO4	54.7	13.2	1.49	H2O	2043	77.2	A + B + C

Notes:
   Table 1  ^a  The composition unit is: mol/100 mol solute.
   Table 1  ^b  The molalities were calculated by the compilers.
   Table 1  ^c  The solid phases are: A=NH₄H₂PO₄; B=KNO₃.
   Table 2  ^a  The composition units are: mol/100 mol of solute.
   Table 2  ^b  The molalities were calculated by the compilers. The unit is: mol kg^–1.
   Table 2  ^c  The solid phases are: A=ice; B=NH₄H₂PO₄; C=KNO₃.

Method/Apparatus/Procedure:
   A visual polythermic method was used.

Source and Purity of Materials:
   Chemically pure materials were recrystallized before use.

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

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Last updated: February 18, 2015 (Created: August 17, 2007)