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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 50 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 50 °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
3.33
0.231
Mg(CHO2)2
0.00
0.00
A
---
---
Co(CHO2)2
Liquid
1.93
0.135
Mg(CHO2)2
2.13
0.194
B
0.02
50.0
Co(CHO2)2
Liquid
1.49
0.105
Mg(CHO2)2
3.24
0.297
B
0.02
50.0
Co(CHO2)2
Liquid
1.35
0.097
Mg(CHO2)2
5.06
0.473
B
0.06
16.67
Co(CHO2)2
Liquid
0.72
0.052
Mg(CHO2)2
6.89
0.652
B
0.04
25.0
Co(CHO2)2
Liquid
0.57
0.042
Mg(CHO2)2
8.58
0.826
B
0.04
25.0
Co(CHO2)2
Liquid
0.38
0.028
Mg(CHO2)2
10.04
0.980
B
0.04
25.0
Co(CHO2)2
Liquid
0.12
0.009
Mg(CHO2)2
12.23
1.220
B
0.03
33.34
Co(CHO2)2
Liquid
0.05
0.004
Mg(CHO2)2
12.98
1.305
B
0.03
33.34
Co(CHO2)2
Liquid
0.00
0.00
Mg(CHO2)2
13.90
1.412
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 solubilities 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).