IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

---

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

---

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) Sodium dihydrogenphosphate; NaH2PO4; [7558-80-7]  NIST Chemistry WebBook for detail
   (4) Sodium nitrate; NaNO3; [7631-99-4]  NIST Chemistry WebBook for detail
   (5) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail

Original Measurements:
   Shpunt, S.Ya., Zh. Prikl. Khim. (Leningrad) 20, 685 (1947).

Variables:

   Concentration = Temperature and composition.

Prepared By:
   J. Eysseltová

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

Part 2. Crystallization temperatures.

Solution number	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)
Section I	-3.9	NaNO3	10 (b)	1.3	NH4H2PO4	--	--	H2O	90	ice
Section I	-5.2	NaNO3	9.6	1.3	NH4H2PO4	4.1	0.41	H2O	86.3	ice
Section I	-6.3	NaNO3	9.1	1.3	NH4H2PO4	9.1	0.97	H2O	81.8	ice
Section I	-7.4	NaNO3	8.7	1.3	NH4H2PO4	13.0	1.44	H2O	78.3	ice
Section I	+3.4	NaNO3	8.1	1.3	NH4H2PO4	18.7	2.22	H2O	73.2	NH4H2PO4
Section I	+11.5	NaNO3	7.8	1.3	NH4H2PO4	21.3	2.61	H2O	70.9	NH4H2PO4
Section I	+16.1	NaNO3	7.7	1.3	NH4H2PO4	23.1	2.90	H2O	69.2	NH4H2PO4
Section I	+19.3	NaNO3	7.5	1.3	NH4H2PO4	24.2	3.08	H2O	68.3	NH4H2PO4
Section I	+22.9	NaNO3	7.4	1.3	NH4H2PO4	25.4	3.29	H2O	67.2	NH4H2PO4
Section I	+25.7	NaNO3	7.3	1.3	NH4H2PO4	26.5	3.48	H2O	66.2	NH4H2PO4
Section I	+28.7	NaNO3	7.2	1.3	NH4H2PO4	27.5	3.66	H2O	65.3	NH4H2PO4
Section I	+31.4	NaNO3	7.1	1.3	NH4H2PO4	28.6	3.87	H2O	64.3	NH4H2PO4
Section II	-7.6	NaNO3	20 (b)	2.9	NH4H2PO4	---	---	H2O	80.0	ice
Section II	-8.6	NaNO3	19.5	2.92	NH4H2PO4	2.0	0.22	H2O	78.5	ice
Section II	-9.8	NaNO3	18.9	2.95	NH4H2PO4	5.6	0.64	H2O	75.5	ice
Section II	-11.0	NaNO3	18.1	2.93	NH4H2PO4	9.1	1.1	H2O	72.8	ice
Section II	-12.0	NaNO3	17.5	2.93	NH4H2PO4	12.3	1.52	H2O	70.2	ice
Section II	+2.3	NaNO3	16.7	2.92	NH4H2PO4	16.0	2.07	H2O	67.3	NH4H2PO4
Section II	+3.5	NaNO3	16.6	2.92	NH4H2PO4	16.6	2.16	H2O	66.8	NH4H2PO4
Section II	+12.1	NaNO3	16.1	2.93	NH4H2PO4	19.3	2.60	H2O	64.6	NH4H2PO4
Section II	+17.2	NaNO3	15.8	2.92	NH4H2PO4	20.6	2.82	H2O	63.6	NH4H2PO4
Section II	+20.6	NaNO3	15.6	2.94	NH4H2PO4	22.0	3.06	H2O	62.4	NH4H2PO4
Section II	+25.1	NaNO3	15.3	2.92	NH4H2PO4	23.1	3.26	H2O	61.6	NH4H2PO4
Section II	+29.3	NaNO3	15.1	2.93	NH4H2PO4	24.2	3.47	H2O	60.7	NH4H2PO4
Section III	-13.4	NaNO3	30b	5.0	NH4H2PO4	--	--	H2O	70.0	ice
Section III	-15.0	NaNO3	28.8	5.03	NH4H2PO4	3.8	0.49	H2O	67.4	ice
Section III	-16.2	NaNO3	27.6	5.00	NH4H2PO4	7.4	0.99	H2O	65.0	ice
Section III	-16.9	NaNO3	27.1	5.00	NH4H2PO4	9.1	1.2	H2O	63.8	ice + NH4H2PO4
Section III	-12.0	NaNO3	26.7	5.02	NH4H2PO4	10.7	1.49	H2O	62.6	NH4H2PO4
Section III	-5.6	NaNO3	26.2	5.00	NH4H2PO4	12.2	1.72	H2O	61.6	NH4H2PO4
Section III	+3.3	NaNO3	25.5	5.01	NH4H2PO4	14.6	2.12	H2O	59.9	NH4H2PO4
Section III	+6.1	NaNO3	25.4	5.03	NH4H2PO4	15.2	2.22	H2O	59.4	NH4H2PO4
Section III	+12.0	NaNO3	24.9	5.01	NH4H2PO4	16.6	2.47	H2O	58.5	NH4H2PO4
Section III	+18.0	NaNO3	24.4	5.01	NH4H2PO4	18.3	2.78	H2O	57.3	NH4H2PO4
Section III	+21.7	NaNO3	24.1	5.01	NH4H2PO4	19.3	2.96	H2O	56.6	NH4H2PO4
Section III	+27.9	NaNO3	23.7	5.01	NH4H2PO4	20.6	3.21	H2O	55.7	NH4H2PO4
Section IV	-8.0	NaNO3	40 (b)	7.8	NH4H2PO4	--	--	H2O	60.0	NaNO3
Section IV	-6.0	NaNO3	38.5	7.85	NH4H2PO4	3.8	0.57	H2O	57.7	NaNO3
Section IV	-4.7	NaNO3	37.8	7.86	NH4H2PO4	5.6	0.86	H2O	56.6	NaNO3
Section IV	-3.0	NaNO3	36.4	7.86	NH4H2PO4	9.1	1.5	H2O	54.5	NaNO3
Section IV	+1.6	NaNO3	35.1	7.82	NH4H2PO4	12.1	1.99	H2O	52.8	NH4H2PO4
Section IV	+9.9	NaNO3	34.4	7.81	NH4H2PO4	13.8	2.32	H2O	51.8	NH4H2PO4
Section IV	+16.2	NaNO3	33.8	7.80	NH4H2PO4	15.2	2.59	H2O	51.0	NH4H2PO4
Section IV	+22.5	NaNO3	33.3	7.82	NH4H2PO4	16.6	2.88	H2O	50.1	NH4H2PO4
Section IV	+28.0	NaNO3	32.7	7.80	NH4H2PO4	18.0	3.17	H2O	49.3	NH4H2PO4
Section V	+4.2	NaNO3	43b	8.9	NH4H2PO4	--	--	H2O	57.0	NaNO3
Section V	+5.3	NaNO3	42.1	8.86	NH4H2PO4	2.0	0.31	H2O	55.9	NaNO3
Section V	+5.9	NaNO3	41.3	8.85	NH4H2PO4	3.8	0.60	H2O	54.9	NaNO3
Section V	+7.5	NaNO3	39.8	8.87	NH4H2PO4	7.4	1.2	H2O	52.8	NaNO3
Section V	+9.1	NaNO3	38.3	8.84	NH4H2PO4	10.7	1.82	H2O	51.0	NaNO3
Section V	+13.8	NaNO3	37.0	8.85	NH4H2PO4	13.8	2.44	H2O	49.2	NH4H2PO4
Section V	+20.7	NaNO3	36.4	8.85	NH4H2PO4	15.2	2.73	H2O	48.4	NH4H2PO4
Section V	+26.2	NaNO3	36.0	8.86	NH4H2PO4	16.2	2.95	H2O	47.8	NH4H2PO4
Section V	+32.4	NaNO3	35.2	8.85	NH4H2PO4	18.0	3.34	H2O	46.8	NH4H2PO4
Section VI	+19.1	NaNO3	46.7 (b)	10.3	NH4H2PO4	---	---	H2O	53.3	NaNO3
Section VI	+20.1	NaNO3	44.9	10.3	NH4H2PO4	3.8	0.64	H2O	51.3	NaNO3
Section VI	+20.7	NaNO3	43.3	10.3	NH4H2PO4	7.3	1.3	H2O	49.4	NaNO3
Section VI	+21.9	NaNO3	41.7	10.3	NH4H2PO4	10.7	1.95	H2O	47.6	NaNO3
Section VI	+24.5	NaNO3	39.6	10.3	NH4H2PO4	15.0	2.87	H2O	45.4	NH4H2PO4
Section VI	+32.4	NaNO3	38.9	10.3	NH4H2PO4	16.6	3.24	H2O	44.5	NH4H2PO4
Section VI	+37.1	NaNO3	38.3	10.3	NH4H2PO4	18.0	3.58	H2O	43.7	NH4H2PO4
Section VII	-1.8	NaNO3	--	--	NH4H2PO4	6.0b	0.55	H2O	94.0	ice
Section VII	-5.5	NaNO3	9.1	1.3	NH4H2PO4	5.5	0.56	H2O	85.4	ice
Section VII	-9.0	NaNO3	16.6	2.49	NH4H2PO4	5.0	0.55	H2O	78.4	ice
Section VII	-11.7	NaNO3	23.1	3.76	NH4H2PO4	4.7	0.57	H2O	72.2	ice
Section VII	-14.7	NaNO3	28.6	5.01	NH4H2PO4	4.3	0.56	H2O	67.1	ice
Section VII	-17.4	NaNO3	33.3	6.25	NH4H2PO4	4.0	0.55	H2O	62.7	ice
Section VII	-10.4	NaNO3	37.5	7.52	NH4H2PO4	3.8	0.56	H2O	58.7	NaNO3
Section VII	+4.1	NaNO3	41.2	8.78	NH4H2PO4	3.6	0.57	H2O	55.2	NaNO3
Section VII	+18.0	NaNO3	44.4	9.99	NH4H2PO4	3.3	0.55	H2O	52.3	NaNO3
Section VIII	-2.8	NaNO3	--	--	NH4H2PO4	10.0b	0.966	H2O	90.0	ice
Section VIII	-6.5	NaNO3	9.1	1.3	NH4H2PO4	9.1	0.97	H2O	81.8	ice
Section VIII	-10.0	NaNO3	16.6	2.60	NH4H2PO4	8.4	0.97	H2O	75.0	ice
Section VIII	-13.2	NaNO3	23.1	3.93	NH4H2PO4	7.7	0.97	H2O	69.2	ice
Section VIII	-16.5	NaNO3	28.6	5.23	NH4H2PO4	7.1	0.96	H2O	64.3	ice
Section VIII	-19.0	NaNO3	33.3	6.52	NH4H2PO4	6.6	0.95	H2O	60.1	ice
Section VIII	-5.3	NaNO3	37.5	7.84	NH4H2PO4	6.2	0.96	H2O	66.3	NaNO3
Section VIII	+9.3	NaNO3	41.2	9.15	NH4H2PO4	5.8	0.95	H2O	53.0	NaNO3
Section VIII	+22.5	NaNO3	44.4	10.4	NH4H2PO4	5.5	0.95	H2O	50.1	NaNO3

Part 3. Solubility isotherms in the NaNO₃-NH₄H₂PO₄-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)(c)
-10	NaNO3	23.1	3.53	NH4H2PO4	---	---	H2O	76.9	A

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)(c)
-10	NaNO3	19.2	2.98	NH4H2PO4	4.9	0.56	H2O	75.9	A
-10	NaNO3	18.6	2.92	NH4H2PO4	6.5	0.75	H2O	74.9	A
-10	NaNO3	16.7	2.62	NH4H2PO4	8.3	0.96	H2O	75.0	A
-10	NaNO3	13.5	2.16	NH4H2PO4	13.1	1.55	H2O	73.4	A + B
-10	NaNO3	17.4	2.92	NH4H2PO4	12.6	1.56	H2O	70.0	B
-10	NaNO3	26.6	5.01	NH4H2PO4	10.9	1.52	H2O	62.5	B
-10	NaNO3	33.9	7.08	NH4H2PO4	9.8	1.5	H2O	56.3d	B + D
-10	NaNO3	34.4	7.23	NH4H2PO4	9.6	1.5	H2O	56.0d	C + D
-10	NaNO3	36.3	7.47	NH4H2PO4	6.5	0.99	H2O	57.2	C
-10	NaNO3	37.6	7.55	NH4H2PO4	3.8	0.56	H2O	58.6	C
-10	NaNO3	39.8	7.78	NH4H2PO4	---	---	H2O	60.2	C
0	NaNO3	---	---	NH4H2PO4	18.4	1.96	H2O	81.6	B
0	NaNO3	8.2	1.3	NH4H2PO4	17.1	1.99	H2O	74.7	B
0	NaNO3	12.15	1.990	NH4H2PO4	16.03	1.940	H2O	71.82d	B
0	NaNO3	16.7	2.90	NH4H2PO4	15.5	1.99	H2O	67.8	B
0	NaNO3	24.58	4.714	NH4H2PO4	14.08	1.995	H2O	61.34d	B
0	NaNO3	25.8	5.02	NH4H2PO4	13.7	1.97	H2O	60.5	B
0	NaNO3	36.36	8.271	NH4H2PO4	11.92	2.003	H2O	51.72d	B + C
0	NaNO3	36.4	8.30	NH4H2PO4	12.0	2.02	H2O	51.6	B + C
0	NaNO3	38.8	8.31	NH4H2PO4	6.3	1.0	H2O	54.9	C
0	NaNO3	39.24	8.383	NH4H2PO4	5.69	0.898	H2O	55.07d	C
0	NaNO3	40.0	8.34	NH4H2PO4	3.6	0.55	H2O	56.4	C
0	NaNO3	41.9	8.48	NH4H2PO4	---	---	H2O	58.1	C
10	NaNO3	---	---	NH4H2PO4	21.8	2.42	H2O	78.2	B
10	NaNO3	7.9	1.3	NH4H2PO4	20.8	2.54	H2O	71.3	B
10	NaNO3	16.2	2.92	NH4H2PO4	18.6	2.48	H2O	65.2	B
10	NaNO3	17.2	3.03	NH4H2PO4	16.1	2.10	H2O	66.7	B
10	NaNO3	34.5	7.85	NH4H2PO4	13.8	2.32	H2O	51.7	B
10	NaNO3	37.5	8.88	NH4H2PO4	12.8	2.24	H2O	49.7	B + C
10	NaNO3	41.4	9.24	NH4H2PO4	5.9	0.97	H2O	52.7	C
10	NaNO3	42.5	9.26	NH4H2PO4	3.5	0.56	H2O	54.0	C
10	NaNO3	43.9	9.21	NH4H2PO4	---	---	H2O	56.1	C
20	NaNO3	---	---	NH4H2PO4	25.9	3.03	H2O	74.1	B
20	NaNO3	7.6	1.3	NH4H2PO4	24.1	3.06	H2O	68.3	B
20	NaNO3	15.7	2.95	NH4H2PO4	21.6	2.99	H2O	62.7	B
20	NaNO3	18.65	3.642	NH4H2PO4	21.1	3.03	H2O	60.3d	B
20	NaNO3	24.4	5.05	NH4H2PO4	18.8	2,87	H2O	56.8	B
20	NaNO3	33.7	7.88	NH4H2PO4	16.0	2.76	H2O	50.3	B
20	NaNO3	36.5	8.85	NH4H2PO4	15.0	2.68	H2O	48.5	B
20	NaNO3	37.50	9.195	NH4H2PO4	14.52	2.622	H2O	47.98d	B
20	NaNO3	38.81	9.802	NH4H2PO4	14.61	2.718	H2O	46.58d	B + C
20	NaNO3	38.9	9.80	NH4H2PO4	14.4	2.67	H2O	46.7d	B + C
20	NaNO3	40.87	9.793	NH4H2PO4	10.03	1.770	H2O	49.1d	C
20	NaNO3	43.8	10.2	NH4H2PO4	5.6	0.96	H2O	50.6	C
20	NaNO3	44.56	10.27	NH4H2PO4	4.38	0.743	H2O	51.06d	C
20	NaNO3	45.2	10.3	NH4H2PO4	3.2	0.54	H2O	51.6	C
20	NaNO3	46.0	10.0	NH4H2PO4	---	---	H2O	54.0	C
30	NaNO3	---	---	NH4H2PO4	30.2	3.76	H2O	69.8	B
30	NaNO3	7.2	1.3	NH4H2PO4	28.0	3.76	H2O	64.8	B
30	NaNO3	15.2	2.96	NH4H2PO4	24.4	3.51	H2O	60.4	B
30	NaNO3	23.6	5.04	NH4H2PO4	21.3	3.36	H2O	55.1	B
30	NaNO3	32.6	7.83	NH4H2PO4	18.4	3.26	H2O	49.0	B
30	NaNO3	35.5	8.85	NH4H2PO4	17.3	3.19	H2O	47.2	B
30	NaNO3	39.0	10.2	NH4H2PO4	16.1	3.12	H2O	44.9	B
30	NaNO3	40.0	10.6	NH4H2PO4	15.5	3.03	H2O	44.5	C + D
30	NaNO3	46.2	11.2	NH4H2PO4	5.4	0.97	H2O	48.4	C
30	NaNO3	47.4	11.3	NH4H2PO4	3.1	0.54	H2O	49.5	C
30	NaNO3	48.0	10.9	NH4H2PO4	---	---	H2O	52.0	C
40 (d)	NaNO3	---	---	NH4H2PO4	34.3	4.54	H2O	65.7	B
40 (d)	NaNO3	6.72	1.27	NH4H2PO4	31.07	4.341	H2O	62.21	B
40 (d)	NaNO3	14.69	3.012	NH4H2PO4	27.93	4.231	H2O	57.38	B
40 (d)	NaNO3	30.55	7.486	NH4H2PO4	21.44	3.882	H2O	48.01	B
40 (d)	NaNO3	41.48	11.81	NH4H2PO4	17.19	3.615	H2O	41.33	B + C
40 (d)	NaNO3	42.2	11.9	NH4H2PO4	15.97	3.319	H2O	41.83	C
40 (d)	NaNO3	45.15	11.86	NH4H2PO4	10.07	1.955	H2O	44.78	C
40 (d)	NaNO3	48.3	12.2	NH4H2PO4	5.05	0.941	H2O	46.65	C
40 (d)	NaNO3	51.3	12.4	NH4H2PO4	---	---	H2O	48.7	C
60 (d)	NaNO3	---	---	NH4H2PO4	43.8	6.77	H2O	56.2	B
60 (d)	NaNO3	11.24	2.583	NH4H2PO4	37.57	6.380	H2O	51.19	B
60 (d)	NaNO3	23.21	5.983	NH4H2PO4	31.15	5.933	H2O	45.64	B
60 (d)	NaNO3	34.2	10.1	NH4H2PO4	26.1	5.71	H2O	39.7	B
60 (d)	NaNO3	42.97	14.54	NH4H2PO4	22.27	5.569	H2O	34.76	B + C
60 (d)	NaNO3	44.93	14.61	NH4H2PO4	18.90	4.542	H2O	36.17	C
60 (d)	NaNO3	47.8	14.9	NH4H2PO4	14.39	3.308	H2O	37.8	C
60 (d)	NaNO3	50.04	14.28	NH4H2PO4	8.72	1.84	H2O	41.24	C
60 (d)	NaNO3	55.55	14.70	NH4H2PO4	---	---	H2O	44.45	C
80 (d)	NaNO3	---	---	NH4H2PO4	53.6	10.0	H2O	46.4	B
80 (d)	NaNO3	15.08	4.341	NH4H2PO4	44.05	9.369	H2O	40.87	B
80 (d)	NaNO3	30.0	10.3	NH4H2PO4	35.7	9.05	H2O	34.3	B
80 (d)	NaNO3	43.28	17.74	NH4H2PO4	28.02	8.487	H2O	28.7	B + C
80 (d)	NaNO3	51.6	18.1	NH4H2PO4	14.94	3.881	H2O	33.46	C
80 (d)	NaNO3	56.47	18.34	NH4H2PO4	7.30	1.75	H2O	36.23	C
80 (d)	NaNO3	59.68	17.41	NH4H2PO4	---	---	H2O	40.32	C
110 (d)	NaNO3	---	---	NH4H2PO4	67.3	17.9	H2O	32.7	B
110 (d)	NaNO3	26.27	13.48	NH4H2PO4	50.8	19.3	H2O	22.9	B
110 (d)	NaNO3	43.33	30.11	NH4H2PO4	39.74	20.40	H2O	16.93	B + C
110 (d)	NaNO3	57.28	26.08	NH4H2PO4	16.88	5.678	H2O	25.84	C
110 (d)	NaNO3	65.7	22.5	NH4H2PO4	---	---	H2O	34.3	C

Part 4. Solutions coexisting with two or three solid phases

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)(c)
-7.8	NaNO3	8.6	1.3	NH4H2PO4	14.7	1.67	H2O	76.7	A + B
-12.0	NaNO3	17.6	2.95	NH4H2PO4	12.1	1.50	H2O	70.3	A + B
-16.9	NaNO3	27.2	5.03	NH4H2PO4	9.2	1.3	H2O	63.6	A + B
+9.9	NaNO3	37.4	8.84	NH4H2PO4	12.8	2.23	H2O	49.8	B + C
+22.8	NaNO3	39.8	10.3	NH4H2PO4	14.7	2.81	H2O	45.5	B + C
-18.4	NaNO3	35.6	6.92	NH4H2PO4	3.9	0.56	H2O	60.5	A + C
-19.5	NaNO3	34.1	6.74	NH4H2PO4	6.4	0.94	H2O	59.5	A + C
-1.4	NaNO3	35.4	7.80	NH4H2PO4	11.2	1.82	H2O	53.4	B + C + D
-20.0	NaNO3	32.7	6.47	NH4H2PO4	7.8	1.1	H2O	59.5	A + B + D
-20.6	NaNO3	33.3	6.67	NH4H2PO4	8.0	1.2	H2O	58.7	A + C + D

Notes:
   Table 4  ^a  These values were calculated by the compiler.
   Table 4  ^b  For these points the salt content was given as "-----" in the original article. The compiler believes this to be an error and that the values should be those given in this table.
   Table 4  ^c  The solid phases are: A=ice; B=NH₄H₂PO₄; C=NaNO₃; D=NaH₂PO₄·2H₂O.
   Table 4  ^d  These data were obtained by the isothermic method. The rest of the data were obtained by the polyhermic method.

Method/Apparatus/Procedure:
   A visual polythermic method and the isothermal method were used but no details are given.

Source and Purity of Materials:
   No information is given.

Estimated Errors:
   Solubility: No information given.
   Temperature: No information is given. The compiler believes the reproducibility of the analyses to be about 1%.

---

Distributed by the Office of Data and Informatics of the National Institute of Standards and Technology (NIST) Material Measurement Laboratory (MML).
Website is owned by NIST (an agency of the U.S. Department of Commerce)

---

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