IUPAC-NIST Solubility Database
NIST Standard Reference Database 106


Glass Ball as Bullet Solubility System: Copper(II)formate with Ammonium formate and Formic acid

Components:
   (1) Ammonium formate; NH4CHO2; [540-69-2]  NIST Chemistry WebBook for detail
   (2) Formic acid; CH2O2; [64-18-6]  NIST Chemistry WebBook for detail
   (3) Copper(II) formate; Cu(CHO2)2; [544-19-4]  NIST Chemistry WebBook for detail

Original Measurements:
   Davidson, A.W.; Holm, V., J. Am. Chem. Soc. 53, 1350 (1931).

Variables:
   Temperature = 31 ºC to 77 ºC

Prepared By:
   T. A. Ageyeva

Experimental Data:   (Notes on the Nomenclature)
(Please see footnotes following the table(s).)
  
Solubility in the Cu(CHO2)2-NH4CHO2-CH2O2 system.
t/°C100 * Mole Fraction1Mass RatioaSolid Phase(s)
65.00.0760.1Cu(CHO2)2 (b)
71.00.0830.1Cu(CHO2)2 (b)
77.00.0980.1Cu(CHO2)2 (b)
60.00.3190.1973Cu(CHO2)2 (b)
70.50.3990.1973Cu(CHO2)2 (b)
77.20.4650.1973Cu(CHO2)2 (b)
51.51.0160.29752Cu(CHO2)2•3CH2O2
68.51.2860.29752Cu(CHO2)2•3CH2O2
74.01.3650.29752Cu(CHO2)2•3CH2O2
29.01.1790.33542Cu(CHO2)2•3CH2O2
31.01.3080.33542Cu(CHO2)2•3CH2O2
33.01.5010.33542Cu(CHO2)2•3CH2O2
38.51.6800.33542Cu(CHO2)2•3CH2O2
43.01.9500.33542Cu(CHO2)2•3CH2O2
44.02.0040.33542Cu(CHO2)2•3CH2O2
37.01.9900.43752Cu(CHO2)2•3CH2O2
43.52.4700.43752Cu(CHO2)2•3CH2O2
48.52.8160.43752Cu(CHO2)2•3CH2O2
51.53.1310.43752Cu(CHO2)2•3CH2O2
Notes:
   a  R = Number of molecules of NH4CHO2/Number of molecules (NH4CHO2 + CH2O2).
   b  The authors make the following comment about this solid phase: “it contained no ammonia and therefore consisted of Cu(CHO2)2, presumably solvated.”

Method/Apparatus/Procedure:
   The solubility values were measured by the freezing point method.1 Samples of solid phase were prepared for analysis by crystallizing from solution, filtering and drying between porous tiles. A quantitative determination of copper by the electrolytic method was sufficient to fix the composition of the compound.

Source and Purity of Materials:
   The copper salt was prepared by dissolving the basic carbonate in 50% formic acid, heating to expel CO2, cooling to precipitate out the crystals, pressing the crystals between porous tiles and drying them at 348 K for 10 h. The ammonium formate was prepared by passing dry NH3 into 100% formic acid and drying the product over 99% sulfuric acid; melting point = 390-391 K. Formic acid was prepared by treating the 90% acid with B2O3; melting point = 281.4-281.7 K.

Estimated Errors:
   Solubility: No information is given.
   Temperature: ± 0.5 K

References:
   1A. W. Davidson and W. H. McAllister, J. Am. Chem. S. 52, 507 (1930).