SDS Volume (4606)
Volume 73. Metal and Ammonium Formate Systems, p None
Original Measurements
Stoilova, D.; Balarew, C.; Vassileva, V.; Comm. Dept. Chem. Bulg. Acad. Sci. 18, 3 (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 $\ce{Cu^{2+}}$ content of the liquid and solid phases was determined complexometrically using Complexon III at pH 5.5-6.0 and Xylenol Orange as indicators. The $\ce{Mg^{2+}}$ concentration was determined complexometrically using Complexon III at pH 9.5-10 and Eriochrome Black T as indicators, after masking the $\ce{Cu^{2+}}$ with cyanide ions. 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:
- Analytical Reagent grade substances were used. The copper and magnesium formates were obtained by neutralizing dilute formic acid solutions with the corresponding hydroxide carbonates.
Estimated Errors:
Ambient temperature: Not given.
Mass concentration (m/v) (1): The solubility of the salt is 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:
- Magnesium formate, $\ce{ Mg(CHO2)2 }$; [557-39-1] NIST WebBook
- Copper formate, $\ce{ Cu(CHO2)2 }$; [544-19-4] NIST WebBook
- Water, $\ce{ H2O }$; [7732-18-5] NIST WebBook
Experimental Data
Solubility values in the Mg(CHO2)2-Cu(CHO2)2-H2O system at 25°C.
| 100w1 | 100w2 | D2|1 | D1|2 | m1 (mol/kg) | m2 (mol/kg) | Phase (s) () |
|---|---|---|---|---|---|---|
| 11.96 | 0.00 | - | - | 1.188 | 0.00 | A |
| 11.20 | 0.81 | 2.28 | - | 1.113 | 0.06 | B |
| 9.68 | 2.52 | 1.61 | - | 0.964 | 0.187 | B |
| 8.94 | 3.75 | 1.55 | - | 0.895 | 0.280 | B |
| 8.91 | 4.68 | 1.35 | - | 0.902 | 0.353 | B |
| 7.43 | 7.74 | eutonic | eutonic | 0.766 | 0.594 | B + C |
| 6.10 | 7.52 | - | 0.06 | 0.618 | 0.567 | D |
| 4.42 | 7.47 | - | 0.05 | 0.439 | 0.552 | D |
| 1.50 | 8.11 | - | 0.05 | 0.145 | 0.584 | D |
| 0.00 | 8.80 | - | - | 0.00 | 0.628 | E |
(a) The molality values were calculated by the compilers.
(b) The solid phases are: A = Mg(CHO2)2·2H2O; B = (Mg,Cu)(CHO2)2·2H2O; C = (Cu,Mg)(CHO2)2·2H2O; D = (Cu,Mg)(CHO2)2·4H2O; E = Cu(CHO2)2·4H2O.
