IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

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 Solubility System: Ammonium dihydrogenphosphate with Potassium dihydrogenphosphate and Water

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Components:
   (1) Ammonium dihydrogenphosphate; NH4H2PO4; [7722-76-1]  NIST Chemistry WebBook for detail
   (2) Potassium dihydrogenphosphate; KH2PO4; [7778-77-0]  NIST Chemistry WebBook for detail
   (3) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail

Original Measurements:
   Shenkin, Ya.S.; Ruchnova, S.A.; Rodionova, N.A., Zh. Neorg. Khim. 1972, 17, 3368.

Variables:

   Concentration = Composition and temperature at atmospheric pressure

Prepared By:
   J. Eysseltová

Experimental Data:   (Notes on the Nomenclature)
  

Composition and boiling points of saturated solutions in the NH₄H₂PO₄-KH₂PO₄-H₂O system.

Boiling Point/°C	Chemical1	102 * Mass Fraction w1	m1 [mol/kg]	Chemical2	102 * Mass Fraction w2	m2 [mol/kg]	Chemical3	102 * Mass Fraction w3
105.1	NH4H2PO4	0	0	KH2PO4	52.70	8.18	H2O	47.30
105.3	NH4H2PO4	3.28	0.63	KH2PO4	51.78	8.46	H2O	44.94
106.2	NH4H2PO4	6.90	1.37	KH2PO4	49.40	8.30	H2O	43.70
105.7	NH4H2PO4	10.67	2.21	KH2PO4	47.46	8.32	H2O	41.87
106.9	NH4H2PO4	15.52	3.38	KH2PO4	44.58	8.20	H2O	39.90
107.1	NH4H2PO4	17.57	3.93	KH2PO4	43.60	8.25	H2O	38.83
108.0	NH4H2PO4	19.70	4.54	KH2PO4	42.60	8.30	H2O	37.70
108.9	NH4H2PO4	25.94	6.39	KH2PO4	38.78	8.07	H2O	35.28
108.6	NH4H2PO4	28.00	7.25	KH2PO4	38.44	8.41	H2O	33.56
106.6	NH4H2PO4	29.39	7.65	KH2PO4	37.23	8.19	H2O	33.38
108.8	NH4H2PO4	32.76	8.91	KH2PO4	35.31	8.12	H2O	31.93
108.8	NH4H2PO4	31.69	8.28	KH2PO4	35.08	7.75	H2O	33.23
106.4	NH4H2PO4	34.56	9.15	KH2PO4	32.64	7.31	H2O	32.80
106.9	NH4H2PO4	36.86	9.83	KH2PO4	30.57	6.89	H2O	32.57
109.7	NH4H2PO4	40.23	11.05	KH2PO4	28.15	6.54	H2O	31.62
110.6	NH4H2PO4	41.87	12.04	KH2PO4	27.92	6.79	H2O	30.21
109.8	NH4H2PO4	42.86	12.39	KH2PO4	27.09	6.62	H2O	30.05
110.3	NH4H2PO4	44.42	12.77	KH2PO4	25.36	6.16	H2O	30.22
109.5	NH4H2PO4	45.32	13.17	KH2PO4	24.79	6.09	H2O	29.89
109.4	NH4H2PO4	48.85	14.52	KH2PO4	21.91	5.50	H2O	29.24
111.4	NH4H2PO4	49.59	14.28	KH2PO4	20.24	4.92	H2O	30.17
110.9	NH4H2PO4	53.69	17.13	KH2PO4	19.07	5.14	H2O	27.24
112.0	NH4H2PO4	54.27	16.42	KH2PO4	17.01	4.35	H2O	28.72
109.6	NH4H2PO4	55.91	16.60	KH2PO4	14.82	3.72	H2O	29.27
110.8	NH4H2PO4	56.57	17.12	KH2PO4	14.71	3.76	H2O	28.72
110.4	NH4H2PO4	62.15	18.25	KH2PO4	8.26	2.05	H2O	29.59
109.9	NH4H2PO4	65.35	20.41	KH2PO4	6.83	1.80	H2O	27.82
110.5	NH4H2PO4	68.30	18.72	KH2PO4	0	0	H2O	31.70

Method/Apparatus/Procedure:
   The method used to determine the solubility has been described earlier (1).

Source and Purity of Materials:
   Chemically pure KH₂PO₄ and NH₄H₂PO₄ were used.

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

References:
   ¹Shenkin, Ya.S.; Ruchnova, S.A.; Shenkina, A.P. Zh. Neorg. Khim. 1968, ₁₃, 256.

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