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IUPAC-NIST Solubility Database
NIST Standard Reference Database 106
Solubility System:
Copper formate with Zinc formate and Water
Components:
(1) Copper formate; Cu(CHO2)2; [544-19-4]
NIST Chemistry WebBook
for detail
(2) Water; H2O; [7732-18-5]
NIST Chemistry WebBook
for detail
(3) Zinc formate; Zn(CHO2)2; [557-41-5]
NIST Chemistry WebBook
for detail
Original Measurements:
Stoilova, D.; Gentcheva, G., J. Solid State Chem. 100, 24-9 (1992).
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 Cu(CHO
2
)
2
-Zn(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
Cu2+/Zn2+
Distribution Coefficient
Zn2+/Cu2+
Cu(CHO2)2
Liquid
---
---
Zn(CHO2)2
8.06
0.564
A
---
---
Cu(CHO2)2
Liquid
2.59
0.186
Zn(CHO2)2
6.89
0.490
B
0.26
3.84
Cu(CHO2)2
Liquid
5.88
0.433
Zn(CHO2)2
5.80
0.423
B
0.19
5.26
Cu(CHO2)2
Liquid
9.43
0.721
Zn(CHO2)2
5.44
0.411
B
0.20
5.00
Cu(CHO2)2
Liquid
13.63
1.075
Zn(CHO2)2
3.79
0.295
B
0.17
5.88
Cu(CHO2)2
Liquid
19.19
1.609
Zn(CHO2)2
3.16
0.262
B
0.12
8.32
Cu(CHO2)2
Liquid
23.85
2.123
Zn(CHO2)2
3.00
0.264
B
0.14
7.14
Cu(CHO2)2
Liquid
25.06
2.265
Zn(CHO2)2
2.89
0.258
eutonic
Cu(CHO2)2
Liquid
25.60
2.319
Zn(CHO2)2
2.52
0.226
eutonic
Cu(CHO2)2
Liquid
26.24
2.413
Zn(CHO2)2
2.95
0.268
eutonic
Cu(CHO2)2
Liquid
26.31
2.398
Zn(CHO2)2
2.26
0.204
C
0.37
2.70
Cu(CHO2)2
Liquid
27.63
2.527
Zn(CHO2)2
1.17
0.106
C
0.37
2.70
Cu(CHO2)2
Liquid
27.58
2.493
Zn(CHO2)2
0.38
0.034
C
0.36
2.78
Cu(CHO2)2
Liquid
26.92
2.405
Zn(CHO2)2
0.20
0.018
C
0.33
3.03
Cu(CHO2)2
Liquid
25.17
2.190
Zn(CHO2)2
---
---
C
---
---
Notes:
a
The molality values were calculated by the compilers.
b
The solid phases are: A = Zn(CHO
2
)
2
•2H
2
O; B = (Zn,Cu)(CHO
2
)
2
.•2H
2
O; C = (Cu,Zn)(CHO
2
)
2
•2H
2
O; and D = Cu(CHO
2
)
2
•2H
2
O.
Method/Apparatus/Procedure:
The method used was the isothermal decrease of supersaturation. Equilibrium was reached in about two days. The total copper and zinc formate concentrations of the liquid and solid phases was determined complexometrically at
p
H 5.5-6.0 using Xylenol Orange as indicator. The copper formate concentration was determined iodometrically. The zinc formate concentration was calculated by the difference. The composition of the suction-dried solid phase was determined by using a modification of the Schreinemakers method.
1
The solid phase was also studied by x-ray diffraction.
Source and Purity of Materials:
The metal formates were prepared by the reaction of the corresponding basic carbonate (for copper formate) or the metal oxide (for zinc formate) with dilute formic acid solutions. Analytical grade reagents were used.
Estimated Errors:
Solubility: The solubility of the salts was determined in a slight excess of formic acid (about 1-2 mass %) to suppress salt hydrolysis.
Temperature: Not given.
References:
1
D. Trendafelov and Chr. Balarew, Comm. Dept. Chem. Bulg. Acad. Sci.
1
, 73 (1968).