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IUPAC-NIST Solubility Database
NIST Standard Reference Database 106
Solubility System:
Magnesium formate with Cobalt formate and Water
Components:
(1) Cobalt formate; Co(CHO2)2; [544-18-3]
NIST Chemistry WebBook
for detail
(2) Magnesium formate; Mg(CHO2)2; [557-39-1]
NIST Chemistry WebBook
for detail
(3) Water; H2O; [7732-18-5]
NIST Chemistry WebBook
for detail
Original Measurements:
Stoilova, D.; Balarew, C.; Vassileva, V., St. Russeva, Zh. Neorg. Khim. 26, 1641 (1981).
Variables:
Concentration = Composition at 80 ºC
Prepared By:
Chr. Balarew and St. Trendafilova
Experimental Data:
(Notes on the Nomenclature)
(Please see footnotes following the table(s).)
Solubility values in the Mg(CHO
2
)
2
-Co(CHO
2
)
2
-H
2
O system at 80 °C.
Chemical
1
Phase
Mass Fraction w
1
m
1
[mol kg-1]
a
Chemical
2
Mass Fraction w
2
m
2
[mol kg-1]
a
Solid Phase(s)
b
Distribution Coefficient
Mg2+/Co2+
Distribution Coefficient
Co 2+/Mg2+
Co(CHO2)2
Liquid
4.28
0.300
Mg(CHO2)2
0.00
0.00
A
---
---
Co(CHO2)2
Liquid
2.48
0.176
Mg(CHO2)2
2.93
0.271
B
0.06
16.67
Co(CHO2)2
Liquid
1.69
0.122
Mg(CHO2)2
5.14
0.482
B
0.06
16.67
Co(CHO2)2
Liquid
1.47
0.108
Mg(CHO2)2
7.14
0.683
B
0.08
12.50
Co(CHO2)2
Liquid
0.94
0.071
Mg(CHO2)2
10.27
1.012
B
0.07
14.29
Co(CHO2)2
Liquid
0.63
0.048
Mg(CHO2)2
11.13
1.103
B
0.06
16.67
Co(CHO2)2
Liquid
0.38
0.030
Mg(CHO2)2
14.11
1.443
B
0.08
12.50
Co(CHO2)2
Liquid
0.00
0.00
Mg(CHO2)2
16.52
1.731
C
---
---
Notes:
a
These values were calculated by the compilers.
b
The solid phases are: A = Co(CHO
2
)
2
•2H
2
O; B = (Co,Mg)(CHO
2
)
2
•2H
2
O; C = Mg(CHO
2
)
2
•2H
2
O.
Method/Apparatus/Procedure:
Equilibrium was reached in 15-20 hrs using the isothermal decrease of supersaturation method. The sum of the Mg
2+
and CO
2+
content of both phases was determined using Complexon III at
p
H 9-10 and Eriochrome Black T as indicator. CO
2+
was determined using Complexon III at
p
H 5.5-6.0 with Xylenol Orange as indicator. The composition of the suction-dried mixed crystals was determined by the method of algebraic indirect identification of the solid phase.
1
Source and Purity of Materials:
The cobalt and magnesium formates were prepared by reaction of the basic carbonates with formic acid solutions.
Estimated Errors:
Solubility: The solubilties were determined in a slight excess of formic acid.
Temperature: Not given.
References:
1
D. Trendafelov and Chr. Balarew, Comm. Dept. Chem. Bulg. Acad. Sci.
1
, 73 (1968).