Abstract
This article deals with the insoluble compounds, formed in CuSO 4 -(NH 4 ) 4 P 2 O 7 -H 2 O system. The solutions were analyzed by means of chemical analysis, the precipitate--by means of x-ray diffraction, chemical and thermal analysis, and FTIR spectroscopy. We have established that at least three poorly soluble compounds can form in the system CuSO 4 -(NH 4 ) 4 P 2 O 7 -H 2 O. Their chemical formulae are Cu 2 P 2 O 7 ;5H 2 O and polymorphic Cu 3 (NH 4 ) 2 (P 2 O 7 ) 2 ;3H 2 O. The first modification is most stable when |Cu + P 2 O 7 | = 0.25 M ( n = 1.0), and, in a matter of days, Dimorph A transforms to Dimorph B, which has not been described in any publications.