NIST-IUPAC Solubility Data Series

Compilation - Ammonium dihydrogenphosphate with Sodium dihydrogenphosphate and Water (IUPAC SDS Volume 66)

SDS Volume (2871)

Volume 66. Ammonium Phosphates, p None

Original Measurements

Shpunt, S. Ya.; Zh. Prikl. Khim. 13, 9 (1940).

Variables:

Temperature and composition.

Prepared by:

J. Eysseltová

Method/Apparatus/Procedure:

A standard visual polythermic method and the isothermal method were used but no details are given. The $\ce{P2O5}$ content was determined by a standard method described in the 'NIUIF materials' but no reference is given. The ammonia content was determined by the Kjeldahl method. The sodium ion content was probably determined by difference (compiler).

Source and Purity of Materials:

No information is given.

Estimated Errors:

Ambient temperature: The temperature was controlled to within ±0.2 K.
Mass concentration (m/v) (1): No information given.

Components:

Ammonium dihydrogenphosphate, $\ce{ NH4H2PO4 }$; [7722-76-1] NIST WebBook
Sodium dihydrogenphosphate, $\ce{ NaH2PO4 }$; [7558-80-7] NIST WebBook
Water, $\ce{ H2O }$; [7732-18-5] NIST WebBook

Experimental Data

Part 3. Solubility isotherms.

$T$ (°C)	100w₁	100w₃	$100 x_{1} (\rm{solutes})$ (mol/100 mol)	$100 x_{3} (\rm{solutes})$ (mol/100 mol)	m₁ (mol/kg)	Phase (s) ()
-9.9	32.4	67.6	100.0	1.391 x 10³	3.99	A + C
-9.9	3.6	28.6	67.8	11.7	88.3	1.4 x 10³	0.46	3.51	A
-9.9	7.5	24.6	67.9	24.0	76.0	1.398 x 10³	0.96	3.02	A
-9.9	9.2	22.8	68.0	29.6	70.4	1.402 x 10³	1.18	2.79	A + B
-9.9	8.5	28.4	63.1	23.8	76.2	1.129 x 10³	1.17	3.75	B + C
-9.9	3.4	30.4	66.2	10.4	89.6	1.302 x 10³	0.45	3.83	C
-7	24.2	75.8	100.0	2.092 x 10³	2.66	A
-7	4.0	21.0	75.0	16.5	83.5	1.988 x 10³	0.46	2.33	A
-7	8.4	17.4	74.2	33.5	66.5	1.893 x 10³	0.98	1.95	A
-7	12.3	13.8	73.9	48.1	51.9	1.851 x 10³	1.45	1.56	A + B
-7	10.6	20.8	68.6	34.6	65.4	1.436 x 10³	1.34	2.53	B
-7	8.8	29.4	61.8	23.7	76.3	1.068 x 10³	1.24	3.96	B + C
-7	7.0	29.7	63.3	19.8	80.2	1.14 x 10³	0.96	3.91	C
-7	3.4	31.5	65.1	10.0	90.0	1.239 x 10³	0.45	4.03	C
-7	33.6	66.4	100.0	1.261 x 10³	4.22	C
-4.3	15.1	84.9	100.0	3.745 x 10³	1.48	A
-4.3	8.8	7.0	84.2	56.8	43.2	3.484 x 10³	0.91	0.69	A
-4.3	16.8	83.2	100.0	3.184 x 10³	1.76	A + B
-4.3	15.3	6.6	78.1	70.9	29.1	2.309 x 10³	1.70	0.70	B
-4.3	13.3	13.5	73.2	50.8	49.2	1.782 x 10³	1.58	1.54	B
-4.3	11.4	20.6	68.0	36.4	63.6	1.396 x 10³	1.46	2.52	B
-4.3	9.1	30.3	60.6	23.8	76.2	1.015 x 10³	1.30	4.16	B + C
-4.3	6.9	31.0	62.1	18.9	81.1	1.084 x 10³	0.96	4.16	C
-4.3	3.3	32.8	63.9	9.5	90.5	1.175 x 10³	0.45	4.28	C
-4.3	34.6	65.4	100.0	4.41	C
0	18.4	81.6	100.0	2.833 x 10³	1.96	B
0	16.9	6.4	76.7	73.4	26.6	2.127 x 10³	1.92	0.70	B
0	16.06	9.02	74.92	65.0	35.0	1.941 x 10³	1.86	1.00	B
0	14.7	13.1	72.2	54.0	46.0	1.697 x 10³	1.77	1.51	B
0	13.11	18.46	68.43	42.6	57.4	1.42 x 10³	1.66	2.25	B
0	12.9	20.0	67.1	40.1	59.9	1.333 x 10³	1.67	2.48	B
0	10.53	27.47	62.0	28.5	71.5	1.077 x 10³	1.48	3.69	B
0	10.0	31.1	58.9	25.1	74.9	944	1.48	4.40	B
0	9.64	31.69	58.67	24.1	75.9	937	1.43	4.50	B + C
0	9.8	31.7	58.5	24.3	75.7	931	1.46	4.51	B + C
0	6.7	33.2	60.1	17.4	82.8	999	0.97	4.60	C
0	5.8	33.5	60.7	15.3	84.7	1.024 x 10³	0.83	4.60	C
0	3.2	34.8	62.0	8.8	91.2	1.083 x 10³	0.45	4.68	C
0	2.62	34.84	62.54	7.3	92.7	1.109 x 10³	0.36	4.64	C
0	36.4	63.6	100.0	1.15 x 10³	4.77	C
10	21.8	78.2	100.0	2.288 x 10³	2.42	B
10	20.5	6.2	73.3	77.6	22.4	1.766 x 10³	2.43	0.70	B
10	18.0	12.7	69.3	59.7	40.3	1.47 x 10³	2.26	1.53	B
10	16.1	19.4	64.5	46.4	53.6	1.196 x 10³	2.16	2.51	B
10	12.7	30.2	57.1	30.5	69.5	875	1.93	4.41	B
10	11.5	34.1	54.4	26.0	74.0	788	1.84	5.22	B
10	11.1	35.5	53.4	24.6	75.4	757	1.81	5.54	B + C
10	6.2	38.0	55.8	14.6	85.4	838	0.96	5.67	C
10	3.0	39.5	57.5	7.3	92.7	9E+2	0.45	5.72	C
10	40.5	59.5	100.0	961	5.67	C
20	25.9	74.1	100.0	1.824 x 10³	3.04	B
20	24.2	5.7	70.1	81.4	18.6	1.508 x 10³	3.00	0.68	B
20	21.4	12.1	66.5	64.9	35.1	1.293 x 10³	2.80	1.52	B
20	19.5	18.9	61.6	51.8	48.2	1.048 x 10³	2.75	2.56	B
20	15.8	29.2	55.0	36.1	63.9	806	2.50	4.42	B
20	14.5	32.9	52.6	31.5	68.5	7.3E+2	2.40	5.21	B
20	13.4	36.7	49.9	27.6	72.4	658	2.33	6.13	B
20	12.4	39.1	48.5	24.9	75.1	621	2.22	6.72	B + C
20	5.7	42.9	51.4	12.2	87.8	701	0.96	6.95	C
20	2.8	44.2	53.0	6.2	93.8	7.5E+2	0.45	6.95	C
20	45.3	54.7	100.0	789	6.90	C
30	30.2	69.8	100.0	1.477 x 10³	3.76	B
30	28.0	5.5	66.5	84.0	16.0	1.278 x 10³	3.66	0.70	B
30	26.10	9.77	64.13	73.6	26.4	1.156 x 10³	3.54	1.27	B
30	25.2	11.5	63.3	69.5	30.5	1.116 x 10³	3.46	1.51	B
30	23.0	18.2	58.8	56.9	43.1	9.3E+2	3.40	2.58	B
30	20.0	24.97	55.03	45.6	54.4	802	3.16	3.78	B
30	18.6	28.2	53.2	40.7	59.3	745	3.04	4.42	B
30	17.1	31.9	50.8	36.1	63.9	678	2.96	5.23	B
30	16.2	35.4	48.4	32.3	67.7	617	2.91	6.09	B
30	15.78	35.62	48.60	31.6	68.4	622	2.82	6.11	B
30	13.30	41.89	44.81	24.9	75.1	536	2.58	7.79	B + C
30	13.20	41.60	45.20	24.9	75.1	544	2.54	7.67	B + C
30	9.55	43.75	46.70	18.5	81.5	5.8E+2	1.78	7.80	C
30	6.26	46.50	47.24	12.3	87.7	594	1.15	8.20	C
30	5.2	47.8	47.0	10.2	89.8	588	0.96	8.47	C
30	3.42	48.55	48.03	6.8	93.2	615	0.62	8.42	C
30	2.5	49.0	48.5	5.0	95.0	627	0.45	8.42	C
30	51.2	48.8	100.0	628	8.74	C

(a) The molalities were calculated by the compiler.

(b) The solid phases are: A = ice; B = NH₄H₂PO₄; C = NaH₂PO₄·2H₂O.

(a) The molalities were calculated by the compilers.