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IUPAC-NIST Solubility Database
NIST Standard Reference Database 106
Solubility System:
Ammonia with Phosphoric acid, Sulfuric 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) Sulfuric acid; H2SO4; [7664-93-9]
NIST Chemistry WebBook
for detail
(4) Water; H2O; [7732-18-5]
NIST Chemistry WebBook
for detail
Original Measurements:
Akiyama, T.; Kanzaki, H.; Minagawa, S., Nippon Dojo Hiryogaku Zasshi 49, 243 (1978).
Variables:
Concentration = Composition at 0 ºC, 25 ºC and 50 ºC
Prepared By:
Hiroshi Miyamoto and J. Eysseltová
Experimental Remarks:
Comments and Additional Data
: The solubilities of NH
4
H
2
PO
4
and (NH
4
)
2
HPO
4
in the quaternary system NH
4
H
2
PO
4
-(NH
4
)
2
HPO
4
-(NH
4
)
2
SO
4
-H
2
O in the range of N/PO
4
= 1.0 to 2.0 may be calculated from eqs [1] and [2], respectively. S/(g/100g soln) = 6.76(2 -
M
)A/(5.76 +
M
)[1] S/(g/100g soln) = –7.76(1 -
M
)A/(5.76 +
M
)[2] A is the sum of solubilities of NH
4
H
2
PO
4
and (NH
4
)
2
HPO
4
in the ternary system NH
4
H
2
PO
4
-(NH
4
)
2
HPO
4
-H
2
O for a given value of
M
.
M
=
n
N1
/
n
p
where
nN
1
is the amount of nitrogen in NH
4
H
2
PO
4
and (NH
4
)
2
HPO
4
, and
n
p
is the amount of the phosphate. The amount of nitrogen in (NH
4
)
2
SO
4
is not included in the ratio
nN
1
/
n
p
.
Experimental Data:
(Notes on the Nomenclature)
Composition of saturated solutions in the NH
4
H
2
PO
4
-(NH
4
)
2
HPO
4
-(NH
4
)
2
SO
4
-H
2
O system.
Solution number
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
Composition
4
[N/PO4]
Comment(s)
1
0
N
8.0
P2O5
20.3
SO3
1.2
1.91
0.05 [Composition SO4 / PO4]
2
0
N
8.9
P2O5
26.8
SO3
2.4
1.53
0.08
3
0
N
10.3
P2O5
16.2
SO3
13.3
1.78
0.75
4
0
N
12.2
P2O5
18.5
SO3
17.9
1.61
0.86
5
25
N
10.4
P2O5
31.4
SO3
3.2
1.50
0.09
6
25
N
11.1
P2O5
28.3
SO3
7.0
1.55
0.22
7
25
N
9.9
P2O5
19.9
SO3
9.9
1.64
0.44
8
25
N
11.4
P2O5
18.8
SO3
13.7
1.79
0.65
9
50
N
13.8
P2O5
31.8
SO3
10.6
1.59
0.31
10
50
N
11.0
P2O5
24.8
SO3
12.1
1.37
0.43
11
50
N
18.1
P2O5
26.1
SO3
28.2
1.79
0.96
12
50
N
14.2
P2O5
18.2
SO3
27.5
1.29
1.34
Part 2. The compilers have used the data in Part 1 to calculate the following values.
Solution number
Chemical
1
10
2
* Mass Fraction w
1
m
1
[mol/kg]
Chemical
2
10
2
* Mass Fraction w
2
m
2
[mol/kg]
Chemical
3
10
2
* Mass Fraction w
3
m
3
[mol/kg]
Chemical
4
10
2
* Mass Fraction w
4
1
NH3
9.7
9.4
H3PO4
28.0
4.71
H2SO4
1.5
0.25
H2O
60.8
2
NH3
10.8
12.9
H3PO4
37.0
7.67
H2SO4
2.9
0.61
H2O
49.2
3
NH3
12.5
15.1
H3PO4
22.4
4.68
H2SO4
16.3
3.40
H2O
48.8
4
NH3
14.8
23.1
H3PO4
25.5
6.91
H2SO4
21.9
5.93
H2O
37.7
5
NH3
12.6
18.5
H3PO4
43.4
11.0
H2SO4
3.9
1.0
H2O
40.0
6
NH3
13.5
20.4
H3PO4
39.1
10.3
H2SO4
8.6
2.2
H2O
38.8
7
NH3
12.0
14.6
H3PO4
27.5
5.80
H2SO4
12.1
2.56
H2O
48.4
8
NH3
13.9
18.8
H3PO4
26.0
6.10
H2SO4
16.8
3.94
H2O
43.4
9
NH3
16.8
37.4
H3PO4
43.9
17.0
H2SO4
13.0
5.03
H2O
26.3
10
NH3
13.4
20.9
H3PO4
34.2
9.30
H2SO4
14.8
4.02
H2O
37.6
11
NH3
22.0
174
H3PO4
36.0
49.6
H2SO4
34.5
47.5
H2O
7.4
12
NH3
17.2
42.4
H3PO4
25.1
10.7
H2SO4
33.7
14.4
H2O
23.9
Method/Apparatus/Procedure:
Mixtures of NH
4
H
2
PO
4
, (NH
4
)
2
HPO
4
, (NH
4
)
2
SO
4
and water were placed in glass-stoppered bottles and heated on a water bath at 90 °C. The bottles were allowed to settle at a given temperature for 7 days. (If no crystals had formed, then seed crystals were added and the mixtures were allowed to settle for another 7 days.) Total nitrogen content in the saturated solutions was determined by chemical analysis. The phosphate and sulfate contents were determined as P
2
O
5
and SO
3
, respectively.
Source and Purity of Materials:
Chemically pure ammonium salts were used.
Estimated Errors:
Solubility: Nothing is specified.
Temperature: Nothing is specfied.