CXII.—Metal-ammonia compounds in aqueous solution. Part IV. The influence of temperature on the dissociation of copper-ammonia sulphate
Journal of the Chemical Society Transactions
IT has already been shown (this vol., p. 496) that the distribution of ammonia between water and chloroform at 20° is not quite independent of the concentration, and the variation is exhibited by the distribution coefficient curve on p. 497. I n our first communication (Trans., 1900, "7, 1239), we have shown that a complex compound, probably Cu4NH,*S04, is formed when excess of ammonia is added to a solution of copper sulphate ; this complex compound is dissociable, and only when there is a
... e excess of ammoriia in the solution does the number of fixed ammonia molecules per atom of copper approximate to four. We have been able to follow the extent of this dissociation a t constant temperature with decreasing total ammonia concentration, and now we have endeavoured to ascertain the influence of temperature on the dissociation. On account of the method which we employ, it was impossible to use a temperature much above the ordinary, and we have not deemed it advisable to work above 30°, which is our upper limit. For lower temperatures, we are only limited by the freezing point of the solution, but the lowest temperature at which we found it convenient to work was 109 This gives us a range of ZOO, and it was expected that the extent of dissociation at the lower and higher temperatures would be sufficiently different to indicate the temperature influence.