Interactions of Cations of the Mn(II) — Zn(II) Series with Water in Solutions: Isopiestic and Spectral Results

Abstract

The dependence of the osmotic coefficients ø vs. molality m for Mn(II), Co(II), Ni(II) (Libuś 1969) and Zn(II) (Robinson 1955) perchlorate solutions are presented in Fig. 1. As may be seen the ø values of the investigated salts are practically the same in the whole concentration range. The visible and ultraviolet absorption spectra of Co(C10₄)₂ and Ni(C10₄)₂ solutions are independent of concentration which proves the lack of coordination of perchlorate anions. These data lead to the conclusion that the interactions of the hexaaquocations M(OH₂(²⁺ ₆,(M = Mn Co, Ni and Zn), which exist in these solutions, with surrounding water are practically the same. On the other hand they are distinctly different from those of other divalent non- transition metal cations, namely Ca(II), Sr(II), Ba(II) and Mg(II) (see Fig. 1).