SDS Volume (4643)

Volume 73. Metal and Ammonium Formate Systems, p None

Original Measurements

Stoilova, D.; Gentcheva, G.; J. Solid State Chem. 100, 24-9 (1992).

Variables:

Room Temp: Composition at 50 °C

Prepared by:

St. Trendafilova, Chr. Balarew

Method/Apparatus/Procedure:

The method used was the isothermal decrease of supersaturation. Equilibrium was reached in about two days. The total copper and zinc formate concentrations of the liquid and solid phases was determined complexometrically at pH 5.5-6.0 using Xylenol Orange as indicator. The copper formate concentration was determined iodometrically. The zinc formate concentration was calculated by the difference. The composition of the suction-dried solid phase was determined by using a modification of the Schreinemakers method [1]. The solid phase was also studied by X-ray diffraction.

Source and Purity of Materials:
  1. The metal formates were prepared by the reaction of the corresponding basic carbonate (for copper formate) or the metal oxide (for zinc formate) with dilute formic acid solutions. Analytical grade reagents were used.
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 1-2 mass%) to suppress salt hydrolysis.

References

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

Components:
  1. Copper formate, $\ce{ Cu(CHO2)2 }$; [544-19-4] NIST WebBook
  2. Zinc formate, $\ce{ Zn(CHO2)2 }$; [557-41-5] NIST WebBook
  3. Water, $\ce{ H2O }$; [7732-18-5] NIST WebBook
Experimental Data
Solubility values in the Cu(CHO2)2-Zn(CHO2)2-H2O system at 50°C.
100w1 100w2 D1|2 D2|1 m1 (mol/kg) m2 (mol/kg) Phase (s) ()
-8.06-- 0.564-A
2.596.890.263.84 0.1860.490B
5.885.800.195.26 0.4330.423B
9.435.440.205.00 0.7210.411B
13.633.790.175.88 1.0750.295B
19.193.160.128.32 1.6090.262B
23.853.000.147.14 2.1230.264B
25.062.89-- 2.2650.258Eutonic
25.602.52-- 2.3190.226Eutonic
26.242.95-- 2.4130.268Eutonic
26.312.260.372.70 2.3980.204C
27.631.170.372.70 2.5270.106C
27.580.380.362.78 2.4930.034C
26.920.200.333.03 2.4050.018C
25.17--- -2.190C

(a) The molality values were calculated by the compilers.

(b) The solid phases are: A = Zn(CHO2)2·2H2O; B = (Zn,Cu)(CHO2)2.·2H2O; C = (Cu,Zn)(CHO2)2·2H2O; and D = Cu(CHO2)2·2H2O.

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