IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

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 Solubility System: Ammonia with Phosphoric acid and Water

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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:
   D'Ans, J.; Schreiner, G., Z. Phys. Chem. 1911, 75, 95.

Variables:

   Concentration = Composition at 25 ºC.

Prepared By:
   J. Eysseltová

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

Solubility in the (NH₄)₃PO₄-NH₃-H₃PO₄-H₂O system at 25 °C.

Chemical1	m1 [mol/kg](a)	Chemical2	m2 [mol/kg](a)	Chemical3	102 * Mass Fraction w3(b)	m3 [mol/kg](b)	Chemical4	102 * Mass Fraction w4(b)	m4 [mol/kg](b)	Chemical5	102 * Mass Fraction w5(b)	Solid Phase(s)(c)
NH3	7.42	H3PO4	0.084	NH3	12.6	8.57	H3PO4	0.82	0.097	H2O	86.5	A (d)
NH3	5.02	H3PO4	0.20	NH3	8.55	5.61	H3PO4	2.0	0.22	H2O	89.5	"
NH3	2.95	H3PO4	0.46	NH3	5.04	3.26	H3PO4	4.5	0.51	H2O	90.5	"
NH3	3.04	H3PO4	1.02	NH3	5.18	3.58	H3PO4	10.0	1.20	H2O	84.8	"
NH3	3.32	H3PO4	1.32	NH3	5.65	4.08	H3PO4	12.9	1.62	H2O	81.4	"
NH3	4.78	H3PO4	2.32	NH3	8.14	6.92	H3PO4	22.7	3.36	H2O	69.1	"
NH3	6.48	H3PO4	3.16	NH3	11.0	11.2	H3PO4	31.1	5.45	H2O	58.0	A + B
NH3	6.42	H3PO4	3.23	NH3	10.9	11.2	H3PO4	31.7	5.63	H2O	57.4	B
NH3	6.46	H3PO4	3.74	NH3	11.0	12.3	H3PO4	36.7	7.15	H2O	52.3	B
NH3	6.56	H3PO4	4.01	NH3	11.2	13.2	H3PO4	39.3	8.10	H2O	49.5	B
NH3	7.78	H3PO4	4.34	NH3	11.5	14.8	H3PO4	42.5	9.45	H2O	45.9	B
NH3	7.26	H3PO4	4.83	NH3	12.4	18.0	H3PO4	47.3	12.0	H2O	40.3	B
NH3	7.16	H3PO4	4.82	NH3	12.2	17.6	H3PO4	47.2	11.9	H2O	40.6	B
NH3	7.14	H3PO4	4.83	NH3	12.2	17.6	H3PO4	47.3	11.9	H2O	40.5	B + C
NH3	7.18	H3PO4	4.83	NH3	12.2	17.8	H3PO4	47.3	11.9	H2O	40.4	B + C
NH3	7.14	H3PO4	4.83	NH3	12.2	17.6	H3PO4	47.3	11.9	H2O	40.5	B + C
NH3	7.14 (e)	H3PO4	4.83 (e)	NH3	12.2	17.6	H3PO4	47.3	11.9	H2O	40.5
NH3	7.15 (e)	H3PO4	5.10 (e)	NH3	12.2	18.9	H3PO4	50.0	13.5	H2O	37.8
NH3	6.86 (e)	H3PO4	5.70(e)	NH3	11.7	21.1	H3PO4	55.9	17.6	H2O	32.5
NH3	6.70	H3PO4	6.74	NH3	11.4	29.7	H3PO4	66.1	29.9	H2O	22.5	C (d)
NH3	6.72	H3PO4	4.54	NH3	11.4	15.3	H3PO4	44.5	10.3	H2O	44.1	C
NH3	5.62	H3PO4	3.88	NH3	9.57	10.7	H3PO4	38.0	7.40	H2O	52.4	C
NH3	4.62	H3PO4	3.36	NH3	7.87	7.80	H3PO4	32.9	5.68	H2O	59.2	C (d)
NH3	2.72	H3PO4	2.59	NH3	4.63	3.89	H3PO4	25.4	3.70	H2O	70.0	C
NH3	2.50	H3PO4	2.54	NH3	4.26	3.53	H3PO4	24.9	3.59	H2O	70.9	C
NH3	2.58	H3PO4	4.29	NH3	4.39	4.82	H3PO4	42.0	8.01	H2O	53.6	C
NH3	2.76	H3PO4	6.21	NH3	4.70	8.01	H3PO4	60.9	18.0	H2O	34.4	C
NH3	3.06	H3PO4	7.70	NH3	5.21	15.8	H3PO4	75.5	39.8	H2O	19.3	C
NH3	3.10	H3PO4	7.86	NH3	5.28	17.5	H3PO4	77.0	44.4	H2O	17.7	C (d)

Notes:
   Table 1  ^a  These compositions are expressed as mol/kg of solution.
   Table 1  ^b  These values were calculated by the compiler.
   Table 1  ^c  The solid phases are: A=(NH₄)₃PO₄; B=(NH₄)₂HPO₄; C=NH₄H₂PO₄.
   Table 1  ^d  These solid phases were analyzed.
   Table 1  ^e  Metastable solutions.

Method/Apparatus/Procedure:
   The isothermal method was used. H₃PO₄ was precipitated as NH₄MgPO₄·6H₂O and weighed as Mg₂P₂O₇. Ammonia was distilled into an acid solution and determined volumetrically.

Source and Purity of Materials:
   Commercial materials, pure.

Estimated Errors:
   Solubility: The compiler assumes the reproducibility of the analyses to be about ± 0.5%.
   Temperature: The temperature was controlled to within 0.05 k. No other details are given.

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