English to Russian Science Chemistry; Chem Sci/Eng qualitative analysis

From this article:
http://pubs.acs.org/doi/full/10.1021/acs.jchemed.5b00750
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One begins with an aqueous solution of copper(II) sulfate, in which the species [Cu(H2O)4] 2+ is responsible for the relatively pale-blue color. The concentration of this solution is not critical, but a greater concentration does not result in a more intense color. Then, aqueous ammonia is added, which complexes copper(II) in the deep blue [Cu(NH3)4]2+.

We can assume that the complex ion equilibria in this system can be represented by a single equation in which the Cu(2+) ion combines with four NH3 molecules to form the four-coordinate [формула катиона тетрааминмеди(2+)] complex.
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