IUPAC-NIST Solubilities Database

IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

Solubility System: Copper formate with Cadmium formate and Water

Components:
   (1) Cadmium formate; Cd(CHO2)2; [4464-23-7]  NIST Chemistry WebBook for detail
   (2) Copper formate; Cu(CHO2)2; [544-19-4]  NIST Chemistry WebBook for detail
   (3) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail

Original Measurements:
   Stoilova, D.; Angelov, S., J. Solid State Chem. 82, 60-4 (1989).

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(CHO₂)₂-Cd(CHO₂)₂-H₂O system at 50 °C.
Chemical₁	Phase	Mass Fraction w₁	m₁ [mol kg-1]^a	Chemical₂	Mass Fraction w₂	m₂ [mol kg-1]^a	Solid Phase(s)	Distribution Coefficient^Cd2+/Cu2+
Cu(CHO2)2	Liquid	25.17	2.190	Cd(CHO2)2	---	---	Cu(CHO2)2•2H2O	---
Cu(CHO2)2	Liquid	24.98	2.258	Cd(CHO2)2	3.00	0.206	Cu0.96Cd0.04(CHO2)2•2H2O	0.52
Cu(CHO2)2	Liquid	24.10	2.212	Cd(CHO2)2	4.95	0.345	Cu0.87Cd0.13(CHO2)2•2H2O	0.90
Cu(CHO2)2	Liquid	23.55	2.210	Cd(CHO2)2	7.06	0.503	Cu0.81Cd0.19(CHO2)2•2H2O	1.02
Cu(CHO2)2	Liquid	23.20	2.230	Cd(CHO2)2	9.05	0.660	Cu0.73Cd0.27(CHO2)2•2H2O	1.26
Cu(CHO2)2	Liquid	22.50	2.254	Cd(CHO2)2	2.50	0.950	Cu0.63Cd0.37(CHO2)2•2H2O	1.38
Cu(CHO2)2	Liquid	21.13	2.145	Cd(CHO2)2	4.74	1.135	Cu0.58Cd0.42(CHO2)2•2H2O	1.36
Cu(CHO2)2	Liquid	20.20	2.029	Cd(CHO2)2	14.98	1.142	Cu0.50Cd0.50(CHO2)2.•2H2O	1.56
Cu(CHO2)2	Liquid	18.98	1.876	Cd(CHO2)2	15.14	1.135	Cu0.41Cd0.59(CHO2)2•2H2O	2.40
Cu(CHO2)2	Liquid	16.89	1.686	Cd(CHO2)2	17.89	1.355	Cu0.36Cd0.64(CHO2)2•2H2O	2.21
Cu(CHO2)2	Liquid	14.37	1.430	Cd(CHO2)2	20.19	1.524	Cu0.27Cd0.73(CHO2)2•2H2O	2.50
Cu(CHO2)2	Liquid	10.15	0.981	Cd(CHO2)2	22.49	1.649	Cu0.20Cd0.80(CHO2)2•2H2O	2.33
Cu(CHO2)2	Liquid	5.73	0.531	Cd(CHO2)2	24.05	1.692	Cu0.11Cd0.89(CHO2)2•2H2O	2.49
Cu(CHO2)2	Liquid	---	---	Cd(CHO2)2	27.80	1.902	Cd(CHO2)2•2H2O	---

Notes:
   ^a  The molality values were calculated by the compilers.

Method/Apparatus/Procedure:
   The method used was the isothermal decrease of supersaturation, for about 2 days. About 2 mass % excess of formic acid was used to prevent hydrolysis of the salts. The copper formate was determined iodometrically; the sum of the Cu²⁺ and Cd²⁺ ions was determined complexometrically at pH 5.5- 6 using Xylenol Orange as indicator. The cadmium formate content was calculated by the difference. The composition of the suction-dried mixed crystals was determined by the algebraic indirect identification of the solid phase composition method.¹

Source and Purity of Materials:
   The copper and cadmium formates were prepared by neutralizing dilute solutions of formic acid with the corresponding normal or basic carbonates. Analytical reagent grade materials were used.

Estimated Errors:
   Solubility: Not given.
   Temperature: Not given.

References:
   ¹D. Trendafelov and Chr. Balarew, Comm. Dept. Chem. Bulg. Acad. Sci. 1, 73 (1968).