Distribution of trace amounts of M2+ ions during Co(CH3COO)2·4H2O crystallization

Distribution coefficients (Henderson–Kraček, Khlopin), D2/1, of trace amounts of Ni2+, Mg2+, Cu2+, Zn2+, Mn2+, Cd2+, Ca2+, and Sr2+ have been determined during crystallization of Co(CH3COO)2·4H2O. Their dependencies on some properties of cocrystallizing salts (acetate hydrates) as well as cocrystallizing ions (M2+) have been analyzed. The D2/1 values are comprised in the range of 0.004(DSr)–3.3(DNi) but most of them are less than 0.06. This indicates that most of investigated M2+ ions may be effectively removed in preparation of high-purity cobalt(II) salts. M2+ ions for which |rCo2+−rM2+|/rCo2+>0.05|rCo2+−rM2+|/rCo2+>0.05, cocrystallize with Co(CH3COO)2·4H2O only in slight degree (D2/1 < 0.06). Ions having electron configuration d1–9 cocrystallize with Co(CH3COO)2·4H2O on an average in the considerable greater degree than ions of electron configuration d0 or d10.