Home
Introduction
Search Menu
IUPAC Series (PDF)
Reference
Version History
About the Project
Disclaimer
Contact Us
Acknowledgements
IUPAC-NIST Solubility Database
NIST Standard Reference Database 106
Solubility System:
Diammonium hydrogenphosphate with Urea and Water
Components:
(1) Diammonium hydrogenphosphate; (NH4)2HPO4; [7783-28-0]
NIST Chemistry WebBook
for detail
(2) Urea; CH4N2O; [57-13-6]
NIST Chemistry WebBook
for detail
(3) Water; H2O; [7732-18-5]
NIST Chemistry WebBook
for detail
Original Measurements:
Treshchov, A.G., Dokl. Timiryazevsk. S.-kh. Akad. 29, 402 (1957).
Variables:
Concentration = Temperature and composition.
Prepared By:
L. V. Chernykh and J. Eysseltová
Experimental Data:
(Notes on the Nomenclature)
(Please see footnotes following the table(s).)
Monovariant and invariant points in the (NH
4
)
2
HPO
4
-CO(NH
2
)
2
-H
2
O system
t/°C
Chemical
1
10
2
* Mass Fraction w
1
m
1
[mol/kg]
(a)
Chemical
2
10
2
* Mass Fraction w
2
m
2
[mol/kg]
(a)
Chemical
3
Composition
3
(b)
10
2
* Mass Fraction w
3
Solid Phase(s)
(c)
-11
CO(NH2)2
32.90
8.16
(NH4)2HPO4
0.00
0.00
H2O
680
67.10
A + B
1.1
CO(NH2)2
40.70
11.43
(NH4)2HPO4
0.00
0.00
H2O
489
59.30
B + C
24.4
CO(NH2)2
54.50
19.94
(NH4)2HPO4
0.00
0.00
H2O
279
45.50
C + D
-6.7
CO(NH2)2
0.00
0.00
(NH4)2HPO4
29.60
3.18
H2O
1730
70.40
A + E
-8.6
CO(NH2)2
0.00
0.00
(NH4)2HPO4
4.60
0.37
H2O
1397
95.40
E + F(metastable)
-17.0
CO(NH2)2
25.40
6.79
(NH4)2HPO4
12.30
1.49
H2O
670
62.30
A + B + E
-16.2
CO(NH2)2
26.70
7.74
(NH4)2HPO4
15.90
2.10
H2O
563
57.40
B + E + F
Notes:
Table 1
a
These values were calculated by the compilers.
Table 1
b
The composition unit is: mol/100 mol of solute.
Table 1
c
The solid phases are: A=ice: B=α-CO(NH
2
)
2
; C=β-CO(NH
2
)
2
; D=γ-CO(NH
2
)
2
; E=(NH
4
)
2
HPO
4
·2H
2
O; F=(NH
4
)
2
HPO
4
.
Method/Apparatus/Procedure:
A visual polythermic method was used.
Source and Purity of Materials:
No information is given.
Estimated Errors:
Solubility: No information is given.
Temperature: No information is given.