SDS Volume (4624)
Volume 73. Metal and Ammonium Formate Systems, p None
Original Measurements
Balarew, C.; Stoilova, D.; Vassileva, V.; J. Solid State Chem. 57, 260-6 (1985).
Variables:
Room Temp: Composition at 25 °C
Prepared by:
St. Trendafilova, Chr. Balarew
Method/Apparatus/Procedure:
The method used was the isothermal decrease of supersaturation, under stirring, for 15-20 hrs. The $\ce{Mn^{2+}}$ content of the liquid and solid phases was determined complexometrically at pH 9.5-10 using Eriochrome Black T as indicator after masking $\ce{Co^{2+}}$ as cyanide. The sum of $\ce{Mn^{2+}}$ and $\ce{Co^{2+}}$ was also determined complexometrically using Xylenol Orange as indicator. The composition of the suction-dried solid phase was calculated using the algebraic indirect identification of solid phase composition method [1]. The mixed crystals were also studied by X-ray diffraction.
Source and Purity of Materials:
- The reagents used were of p.a. grade. The manganese and cobalt formates were prepared by action of dilute formic acid on the manganese and cobalt carbonates, respectively.
Estimated Errors:
Ambient temperature: Not given.
Mass concentration (m/v) (1): The solubility of the salts was determined in a slight excess of formic acid (about 2%) to suppress salt hydrolysis.
References
1 Trendafelov, D.; Balarew, Chr.; Comm. Dept. Chem. Bulg. Acad. Sci. 1 , 73 (1968).
Components:
- Manganese(II) formate, $\ce{ Mn(CHO2)2 }$; [3251-96-5] NIST WebBook
- Cobalt formate, $\ce{ Co(CHO2)2 }$; [544-18-3] NIST WebBook
- Water, $\ce{ H2O }$; [7732-18-5] NIST WebBook
Experimental Data
Solubility values in the Mn(CHO2)2-Co(CHO2)2-H2O system at 25°C.
| 100w1 | 100w2 | D1|2 | D2|1 | m1 (mol/kg) | m2 (mol/kg) | Phase (s) () |
|---|---|---|---|---|---|---|
| 6.28 | 0.00 | - | - | 0.462 | 0.00 | A |
| 5.38 | 1.29 | 0.24 | 4.17 | 0.398 | 0.093 | B |
| 3.95 | 1.00 | 0.27 | 3.74 | 0.287 | 0.071 | B |
| 3.84 | 1.11 | 0.28 | 3.57 | 0.279 | 0.078 | B |
| 2.28 | 1.49 | 0.21 | 4.93 | 0.163 | 0.104 | B |
| 0.00 | 2.44 | - | - | 0.00 | 0.168 | C |
(a) The molality values were calculated by the compilers.
(b) The solid phases are: A = Mn(CHO2)2·2H2O; B = (Mn,Co)(CHO2)2·2H2O; C = Co(CHO2)2·2H2O.
