Components:
(1) Nickel formate,
Ni(CHO2)2; [3349-06-2]
NIST WebBook
(2) Copper formate,
Cu(CHO2)2; [544-19-4]
NIST WebBook
(3) Water,
H2O; [7732-18-5]
NIST WebBook
Original Measurements
Stoilova, D.; Risova, D.; Bulg. Chem. Commun. 26, 268-273 (1993).
Variables:
Ambient temperature: Composition at 50 °C
Prepared by:
St. Trendafilova, Chr. Balarew
Method/Apparatus/Procedure:
The solubility was studied by the method of isothermal decrease of supersaturation. The equilibrium was reached in about two days. The liquid phase concentrations were determined as follows: the sum of the copper and cobalt formate concentrations was determined complexometrically at pH 5.5-6.0 using Xylenol orange as indicator, the copper formate concentration was determined iodometrically. The cobalt formate concentration was estimated by difference. The variation of the Schreinemakers method was used for calculation of ideally suction dried solid phase composition.1 X-ray powder analysis and IR spectra were carried out.
Source and Purity of Materials:
- The metal formates were prepared from reaction of the corresponding metal hydroxide carbonates with dilute formic acid solutions at 70-80°C. The crystals were recrystallized in water and dried in air. The reagents used were p.a.(Merck).
Estimated Errors:
Ambient temperature: Not given.
Mass concentration (m/v) (1): The experiments were carried out in presence of a slight excess of formic acid (1-2 mass%) in order to suppress the salt hydrolysis.
References
1 Trendafelov, D.; Balarew, Chr.; Comm. Dept. Chem. Bulg. Acad. Sci. 1 , 73 (1968).
Experimental Values:
Solubility values in the Ni(CHO2)2-Cu(CHO2)2-H2O system at 50°C.
| 100w1 | 100w2 | D2|1 | D1|2 | m2 (mol/kg)a | m1 (mol/kg)a | Phase (s)b |
|---|---|---|---|---|---|---|
| 25.17 | 0.0 | - | - | 2.19 | 0.0 | A |
| 25.03 | 1.15 | 7.2 x 10-1 | 1.39 | 2.207 | 1.05 x 10-1 | B |
| 24.95 | 1.81 | 2.04 | 4.9 x 10-1 | 2.218 | 1.66 x 10-1 | B |
| 22.8 | 2.04 | 3.88 | 2.6 x 10-1 | 1.975 | 1.84 x 10-1 | B |
| 22.54 | 1.97 | 4.57 | 2.2 x 10-1 | 1.944 | 1.75 x 10-1 | B |
| 20.19 | 1.62 | - | - | 1.749 | 1.45 x 10-1 | Eutonic |
| 20.1 | 1.79 | - | - | 1.675 | 1.54 x 10-1 | Eutonic |
| 20.63 | 1.42 | - | - | 1.723 | 1.22 x 10-1 | Eutonic |
| 17.14 | 1.81 | 9.1 | 1.1 x 10-1 | 1.377 | 1.50 x 10-1 | C |
| 12.74 | 2.12 | 9.1 | 1.1 x 10-1 | 9.74 x 10-1 | 1.67 x 10-1 | C |
| 9.69 | 1.91 | 11.76 | 9 x 10-2 | 7.14 x 10-1 | 1.45 x 10-1 | C |
| 6.32 | 1.76 | 11.1 | 9 x 10-2 | 4.48 x 10-1 | 1.29 x 10-1 | C |
| 4.19 | 2.32 | 7.69 | 1.3 x 10-1 | 2.92 x 10-1 | 1.67 x 10-1 | C |
| 2.12 | 3.31 | 5.55 | 1.8 x 10-1 | 1.46 x 10-1 | 2.35 x 10-1 | C |
| 0.0 | 2.78 | - | - | 0.0 | 1.92 x 10-1 | D |
(a) The molality values were calculated by the compilers. (b) The solid phases are: A = Cu(CHO2)2·2H2O; B = (Cu,Ni)(CHO2)2·2H2O; C = (Ni,Cu)(CHO2)2·2H2O; D = Ni(CHO2)2·2H2O.
