Components:
(1) Sodium formate,
NaCHO2; [141-53-7]
NIST WebBook
(2) Cadmium formate,
Cd(CHO2)2; [4464-23-7]
NIST WebBook
(3) Water,
H2O; [7732-18-5]
NIST WebBook
Original Measurements
Itkina, L. S.; Nadzharyan, K. A.; Zh. Neorg. Khim. 26, 515 (1981).
Variables:
Ambient temperature: Composition at 50 °C
Prepared by:
St. Trendafilova, Chr. Balarew
Method/Apparatus/Procedure:
The isothermal method was used. Equilibrium was reached in 2.5 weeks. The sodium content of both phases was determined by flame photometry. The Cd2+ content was determined complexometrically using Eriochrome Black T as the indicator. The composition of the solid phases was determined by Schreinemakers' method, by TG analysis, IR spectroscopy and x-ray diffraction.
Source and Purity of Materials:
- NaCHO2 and Cd(CHO2)2·2H2O were prepared by reacting formic acid with p.a. grade NaOH and CdCO3, respectively. The sodium formate synthesis was carried out in an alkaline medium to prevent formation of the acid salt.
Estimated Errors:
Ambient temperature: The temperature was kept constant to within ±0.1°C.
Experimental Values:
Solubility values in the NaCHO2-Cd(CHO2)2-H2O system at 50°C.
| 100w1 | 100w2 | m1 (mol/kg)b | m2 (mol/kg)b | Phase (s)a |
|---|---|---|---|---|
| 49.97 | - | 14.69 | - | A |
| 50.38 | 1.83 | 15.5 | 1.89 x 10-1 | A + B |
| 45.53 | 1.89 | 12.73 | 1.78 x 10-1 | B |
| 42.26 | 1.92 | 11.14 | 1.75 x 10-1 | B |
| 37.67 | 1.97 | 9.176 | 1.61 x 10-1 | B |
| 33.23 | 2.2 | 7.597 | 1.69 x 10-1 | B |
| 24.45 | 2.68 | 4.933 | 1.82 x 10-1 | B |
| 13.03 | 10.57 | 2.507 | 6.83 x 10-1 | B |
| 9.76 | 16.15 | 1.94 | 1.077 | B |
| 8.05 | 24.83 | 1.76 | 1.827 | B + C |
| 7.5 | 24.47 | 1.62 | 1.777 | C |
| 4.58 | 24.38 | 9.48 x 10-1 | 1.695 | C |
| - | 27.77 | - | 1.899 | C |
(a) The solid phases are: A = NaCHO2; B = NaCd(CHO2)3; C = Cd(CHO2)2ยท2H2O. (b) The molality values were calculated by the compilers.
