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IUPAC-NIST Solubility Database
NIST Standard Reference Database 106
Solubility System:
Cobalt formate with Nickel formate and Water
Components:
(1) Cobalt formate; Co(CHO2)2; [544-18-3]
NIST Chemistry WebBook
for detail
(2) Nickel formate; Ni(CHO2)2; [3349-06-2]
NIST Chemistry WebBook
for detail
(3) Water; H2O; [7732-18-5]
NIST Chemistry WebBook
for detail
Original Measurements:
Balarew, C.; Vassileva, V., Comm. Dept. Chem. Bulg. Acad. Sci. 22, 246 (1989).
Variables:
Concentration = Composition at 25 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 Co(CHO
2
)
2
-Ni(CHO
2
)
2
-H
2
O system at 25 °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
Co2+/Ni2+
Distribution Coefficient
Ni2+/Co2+
Co(CHO2)2
Liquid
2.44
0.168
Ni(CHO2)2
---
---
A
---
---
Co(CHO2)2
Liquid
2.18
0.150
Ni(CHO2)2
0.25
0.017
B
0.61
1.63
Co(CHO2)2
Liquid
1.92
0.132
Ni(CHO2)2
0.40
0.028
B
0.62
1.61
Co(CHO2)2
Liquid
1.68
0.115
Ni(CHO2)2
0.57
0.039
B
0.66
1.52
Co(CHO2)2
Liquid
1.52
0.104
Ni(CHO2)2
0.69
0.047
B
0.76
1.31
Co(CHO2)2
Liquid
1.25
0.086
Ni(CHO2)2
0.92
0.063
B
0.77
1.30
Co(CHO2)2
Liquid
1.09
0.075
Ni(CHO2)2
1.15
0.079
B
0.90
1.11
Co(CHO2)2
Liquid
0.91
0.062
Ni(CHO2)2
1.27
0.087
B
0.93
1.08
Co(CHO2)2
Liquid
0.72
0.049
Ni(CHO2)2
1.44
0.099
B
1.00
1.00
Co(CHO2)2
Liquid
0.48
0.033
Ni(CHO2)2
1.70
0.117
B
1.15
0.87
Co(CHO2)2
Liquid
0.27
0.019
Ni(CHO2)2
1.92
0.132
B
1.28
0.78
Co(CHO2)2
Liquid
---
---
Ni(CHO2)2
2.13
0.146
C
---
---
Notes:
a
The molality values were calculated by the compilers.
b
The solid phases are: A = Co(CHO
2
)
2
•2H
2
O; B = (Co, Ni)(CHO
2
)
2
•2H
2
O; C = Ni(CHO
2
)
2
•2H
2
O.
Method/Apparatus/Procedure:
The method of isothermal decrease of supersaturation was used. The mixtures were stirred for 15-20 hrs. The Ni
2+
was determined gravimetrically with dimethylglyoxime. The sum of the CO
2
+ and Ni
2+
was checked by back titration of the excess Complexon III with zinc sulfate at
p
H 5.5-6.0 using Xylenol Orange as indicator. The composition of the solid phase was calculated by the algebraic indirect identification of the solid phase composition method.
1
Source and Purity of Materials:
Cobalt and nickel formates were prepared by neutralizing dilute formic acid with normal or basic metal carbonates. All reagents were of p.a. grade.
Estimated Errors:
Solubility: The solubilities were determined in a slight excess of formic acid (about 2%) in order to inhibit saly hydrolysis.
Temperature: Not given.
References:
1
D. Trendafelov and Chr. Balarew, Comm. Dept. Chem. Bulg. Acad. Sci.
1
, 73 (1968).