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IUPAC-NIST Solubility Database
NIST Standard Reference Database 106
Solubility System:
Ammonia with Phosphoric acid and Water
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:
Mazunin, S.A.; Sosnina, O.E.; Volkov, A.A.; Danina, T.L., Termicheskiy Analiz i Fazovye Ravnovesiya, Perm, 79 (1985).; Sosnina, O.E.; Volkov, A.A., Uch. Zap. Perm. Gos. Univ., Ser. Khim. 289, 20 (1973).
Variables:
Concentration = Composition at 20 ºC and 60 ºC
Prepared By:
L.V. Chernykh and J. Eysseltová
Experimental Data:
(Notes on the Nomenclature)
(Please see footnotes following the table(s).)
Solubility isotherms in the NH
4
H
2
PO
4
-(NH
4
)
2
HPO
4
-H
2
O system.
t/°C
Chemical
1
10
2
* Mass Fraction w
1
Chemical
2
10
2
* Mass Fraction w
2
Chemical
3
10
2
* Mass Fraction w
3
m
3
[mol/kg]
Chemical
4
10
2
* Mass Fraction w
4
m
4
[mol/kg]
Chemical
5
10
2
* Mass Fraction w
5
Solid Phase(s)
(b)
Refractive Index
20
NH4H2PO4
0.0
(NH4)2HPO4
40.8
NH3 (a)
10.5
10.4
H3PO4 (a)
30.3
5.2
H2O (a)
59.2
A
20
NH4H2PO4
6.0
(NH4)2HPO4
39.0
NH3 (a)
11.0
11.7
H3PO4 (a)
34.1
6.3
H2O (a)
55.0
A
20
NH4H2PO4
9.0
(NH4)2HPO4
38.0
NH3 (a)
11.1
12.3
H3PO4 (a)
35.9
6.9
H2O (a)
53.0
A
20
NH4H2PO4
12.0
(NH4)2HPO4
37.0
NH3 (a)
11.3
13.0
H3PO4 (a)
37.7
7.5
H2O (a)
51.0
A
20
NH4H2PO4
16.0
(NH4)2HPO4
36.0
NH3 (a)
11.6
14.3
H3PO4 (a)
40.3
8.6
H2O (a)
48.0
A
20
NH4H2PO4
26.0
(NH4)2HPO4
32.0
NH3 (a)
12.1
16.9
H3PO4 (a)
45.9
11.2
H2O (a)
42.0
A + B
20
NH4H2PO4
24.0
(NH4)2HPO4
31.5
NH3 (a)
11.7
15.4
H3PO4 (a)
43.8
10.1
H2O (a)
44.5
"
20
NH4H2PO4
25.0
(NH4)2HPO4
23.0
NH3 (a)
9.6
10.9
H3PO4 (a)
38.4
7.5
H2O (a)
52.0
"
20
NH4H2PO4
26.0
(NH4)2HPO4
14.0
NH3 (a)
7.5
7.3
H3PO4 (a)
32.5
5.5
H2O (a)
60.0
"
20
NH4H2PO4
27.0
(NH4)2HPO4
7.0
NH3 (a)
5.8
5.2
H3PO4 (a)
28.2
4.4
H2O (a)
66.0
"
20
NH4H2PO4
27.3
(NH4)2HPO4
0.0
NH3 (a)
4.0
3.3
H3PO4 (a)
23.3
3.3
H2O (a)
72.7
"
60
NH4H2PO4
0.0
(NH4)2HPO4
48.8
NH3 (a)
12.6
14.4
H3PO4 (a)
36.2
7.2
H2O (a)
51.2
A
60
NH4H2PO4
6.5
(NH4)2HPO4
45.7
NH3 (a)
12.8
15.7
H3PO4 (a)
39.4
8.4
H2O (a)
47.8
A
60
NH4H2PO4
13.1
(NH4)2HPO4
42.7
NH3 (a)
13.0
17.2
H3PO4 (a)
42.8
9.9
H2O (a)
44.2
A
60
NH4H2PO4
20.4
(NH4)2HPO4
40.5
NH3 (a)
13.5
20.2
H3PO4 (a)
47.4
12.4
H2O (a)
39.1
A
60
NH4H2PO4
26.7
(NH4)2HPO4
38.3
NH3 (a)
13.8
23.2
H3PO4 (a)
51.2
14.9
H2O (a)
35.0
A
60
NH4H2PO4
35.1
(NH4)2HPO4
35.0
NH3 (a)
14.2
27.9
H3PO4 (a)
55.9
19.1
H2O (a)
29.9
A + B
60
NH4H2PO4
35.7
(NH4)2HPO4
31.8
NH3 (a)
13.5
24.4
H3PO4 (a)
54.0
17.0
H2O (a)
32.5
B
60
NH4H2PO4
36.4
(NH4)2HPO4
25.2
NH3 (a)
11.9
18.2
H3PO4 (a)
49.7
13.2
H2O (a)
38.4
B
60
NH4H2PO4
39.3
(NH4)2HPO4
17.6
NH3 (a)
10.4
14.1
H3PO4 (a)
46.5
11.0
H2O (a)
43.1
B
60
NH4H2PO4
40.8
(NH4)2HPO4
11.2
NH3 (a)
8.9
10.9
H3PO4 (a)
43.1
9.2
H2O (a)
48.0
B
Notes:
Table 1
a
These values were calculated by the compiler.
Table 1
b
The solid phases are: A=(NH
4
)
2
HPO
4
; B=NH
4
H
2
PO
4
.
Method/Apparatus/Procedure:
The refractometric variation of the isothermal method was used. The compilers assume that it was the method described elsewhere.
1
NH
4
H
2
PO
4
and (NH
4
)
2
HPO
4
were determined by potentiometric titration. The composition of the solid phase was determined by the Schreinemaker's method.
Source and Purity of Materials:
No information is given, but the compilers assume that the materials were the same as those used in Ref. 2.
Estimated Errors:
Solubility: The precision of the analysis of NH
4
H
2
PO
4
and (NH
4
)
2
HPO
4
was 0.2% and 0.6%, respectively.
References:
1
Zhuravlev, E.F.; Sheveleva, A.D. Zh. Neorg. Khim. 1960,
5
, 2630.
2
Sosnina, O.E.; Volkov, A.A. Uch. Zap. Perm. Gos. Univ., Ser. Khim. 1973,
289
, 20.