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IUPAC-NIST Solubility Database
NIST Standard Reference Database 106
Solubility System:
Magnesium formate with Cadmium formate and Water
Components:
(1) Cadmium formate; Cd(CHO2)2; [4464-23-7]
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:
Balarew, C.; Vassileva, V.; Stoilova, D., Comm. Dept. Chem. Bulg. Acad. Sci. 14, 57 (1981).
Variables:
Concentration = Composition at 25 ºC
Prepared By:
Chr. Balarew and St. Trendafilova
Experimental Remarks:
The molality values were calculated by the compilers.
Experimental Data:
(Notes on the Nomenclature)
(Please see footnotes following the table(s).)
Solubility values in the Mg(CHO
2
)
2
-Cd(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
Cd2+ / Mg2+
Distribution Coefficient
Mg2+/ Cd2+
Mg(CHO2)2
Liquid
11.99
1.192
Cd(CHO2)2
---
---
A
---
---
Mg(CHO2)2
Liquid
12.26
1.25
Cd(CHO2)2
2.10
0.121
B
1.62
---
Mg(CHO2)2
Liquid
12.01
1.24
Cd(CHO2)2
3.51
0.205
B
1.56
---
Mg(CHO2)2
Liquid
11.52
1.19
Cd(CHO2)2
3.60
0.209
B
1.46
---
Mg(CHO2)2
Liquid
10.75
1.13
Cd(CHO2)2
6.22
0.370
B
1.42
---
Mg(CHO2)2
Liquid
11.02
1.17
Cd(CHO2)2
6.95
0.419
B
eutonic
Mg(CHO2)2
Liquid
10.99
1.18
Cd(CHO2)2
7.79
0.473
C
0.24
Mg(CHO2)2
Liquid
9.64
1.02
Cd(CHO2)2
7.83
0.468
C
0.16
Mg(CHO2)2
Liquid
8.16
0.857
Cd(CHO2)2
8.57
0.508
C
0.12
Mg(CHO2)2
Liquid
6.68
0.691
Cd(CHO2)2
8.73
0.509
C
0.09
Mg(CHO2)2
Liquid
4.36
0.442
Cd(CHO2)2
9.46
0.542
C
0.08
Mg(CHO2)2
Liquid
3.14
0.318
Cd(CHO2)2
10.39
0.593
C
0.08
Mg(CHO2)2
Liquid
---
---
Cd(CHO2)2
12.45
0.702
D
---
Notes:
a
The molality values were calculated by the compilers.
b
The solid phases are: A= Mg(CHO
2
)
2
•2H
2
O; B = (Mg,Cd)(CHO
2
)
2
•2H
2
O; C = (Cd,Mg)(CHO
2
)
2
•2H
2
O; D = Cd(CHO
2
)
2
•2H
2
O.
Method/Apparatus/Procedure:
Equilibrium was reached after about 2 days using the method described earlier.
1
The sum of the Mg
2+
and Cd
2+
content of both phases was determined by a complexometric back titration at
p
H 9-10, using Eriochrome Black T as indicator. Cd
2+
was determined by a complexometric back titration at
p
H 5.5-6.0 using 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 magnesium and cadmium formates were prepared by dissolving basic magnesium or cadmium carbonates in dilute formic acid. All materials were of analytical reagent grade.
Estimated Errors:
Solubility: The solubilities were determined in a slight excess for formic acid (about 2%) in order to inhibit salt hydrolysis.
Temperature: Not given.
References:
1
Chr. Balarew, V. Karaivanova, and T. Oikova, Comm. Dept. Chem. Bulg. Acad. Sci.
3
, 637 (1970).
2
D. Trendafelov and Chr. Balarew, Comm. Dept. Chem. Bulg. Acad. Sci.
1
, 73 (1968).