IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

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 Solubility System: Ammonium dihydrogenphosphate with Ammonium 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) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail

Original Measurements:
   Varlamov, M.L.; Kaganskiy, I.M.; Kashcheeva, I.A.; Manakin, G.A., Zh. Prikl. Khim. (Leningrad) 1973, 46, 2767.

Variables:

   Concentration = Composition at 140 ºC to 170 ºC.

Prepared By:
   J. Eysseltová

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

Solubility in the NH₄H₂PO₄-NH₄NO₃-H₂O system.

t/°C	Chemical1	102 * Mass Fraction w1	m1 [mol/kg](a)	Chemical2	102 * Mass Fraction w2	m2 [mol/kg](a)	Chemical3	102 * Mass Fraction w3	Solid Phase(s)(b)
140	NH4NO3	88.30	298.12	NH4H2PO4	8.00	18.79	H2O	3.70	A
140	NH4NO3	83.90	143.57	NH4H2PO4	8.80	10.48	H2O	7.30	A
140	NH4NO3	77.50	80.68	NH4H2PO4	10.50	7.61	H2O	12.00	A
140	NH4NO3	66.40	48.79	NH4H2PO4	16.60	8.49	H2O	17.00	A
140	NH4NO3	56.00	34.13	NH4H2PO4	23.50	9.96	H2O	20.50	A
140	NH4NO3	45.10	25.38	NH4H2PO4	32.70	12.80	H2O	22.20	A
140	NH4NO3	92.00	383.09	NH4H2PO4	5.00	14.49	H2O	3.00	B
150	NH4NO3	88.0	XX (c)	NH4H2PO4	12.0	XX (c)	H2O	-	B
150	NH4NO3	97.02	612.12	NH4H2PO4	1.00	4.39	H2O	1.98	B
150	NH4NO3	89.82	5610.25	NH4H2PO4	9.98	433.76	H2O	0.20	B
150	NH4NO3	83.0	XX (c)	NH4H2PO4	17.0	XX (c)	H2O	-	A
150	NH4NO3	81.88	143.66	NH4H2PO4	11.00	13.43	H2O	7.12	A
150	NH4NO3	84.29	299.99	NH4H2PO4	12.20	30.21	H2O	3.51	A
150	NH4NO3	70.40	73.29	NH4H2PO4	17.60	12.75	H2O	12.00	A
150	NH4NO3	59.00	49.14	NH4H2PO4	26.00	15.07	H2O	15.00	A
150	NH4NO3	47.90	33.06	NH4H2PO4	34.00	16.33	H2O	18.10	A
160	NH4NO3	95.4	XX (c)	NH4H2PO4	4.6	XX (c)	H2O	-	B
160	NH4NO3	80.0	XX (c)	NH4H2PO4	20.0	XX (c)	H2O	-	A
160	NH4NO3	78.40	612.12	NH4H2PO4	20.00	108.66	H2O	1.60	A
160	NH4NO3	75.07	299.61	NH4H2PO4	21.80	60.54	H2O	3.13	A
160	NH4NO3	64.00	92.97	NH4H2PO4	27.40	27.70	H2O	8.60	A
160	NH4NO3	50.70	50.67	NH4H2PO4	36.80	25.59	H2O	12.50	A
160	NH4NO3	42.00	34.98	NH4H2PO4	43.00	24.92	H2O	15.00	A
170	NH4NO3	66.0	XX (c)	NH4H2PO4	34.0	XX (c)	H2O	-	A
170	NH4NO3	63.11	239.63	NH4H2PO4	33.60	88.78	H2O	3.29	A
170	NH4NO3	46.35	79.32	NH4H2PO4	46.35	55.19	H2O	7.30	A
170	NH4NO3	55.10	137.66	NH4H2PO4	39.90	69.37	H2O	5.00	A

Notes:
   Table 1  ^a  The molalities were calculated by the compiler.
   Table 1  ^b  The solid phases are: A=NH₄H₂PO₄; B=NH₄NO₃.
   Table 1  ^c  The molalities cannot be calculated because the liquid phase is anhydrous.

Method/Apparatus/Procedure:
   A modified polythermic method¹ was used, where heat inertia of the system was eliminated. The compiler assumes that the isotherms were derived graphically from experimental results.

Source and Purity of Materials:
   Chemically pure or reagent grade salts were recrystallized twice and dried at 60 °C. They were further dehydrated with absolute ethanol. They were analyzed for nitrogen (both NH₃ and NO₃^–) and P₂O₅ (no details are given). The m.p. of NH₄NO₃ was checked as 169 ± 0.2 °C.

Estimated Errors:
   Solubility: No information is given.
   Temperature: The difference between the temperature of appearance of the first crystal and disappearance of the last crystal was 1 °C to 3 °C.

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

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