Studies on some physico-chemical properties of the monovalent mendelevium

It was established that Md3+ reduced by Yb2+ or Eu2+ co-crystallizes with NaCl in water-ethanol solutions. The co-crystallization coefficient is independent of the relative quantities of the solid and liquid phase, of the concentration of the reducing agent in the concentration range from 1 to 8 mg/ml, and of the concentration of the chloride ion in the solution. Basing on the knowledge of anomalous mixed crystals and on the thermodynamical analysis of the formation of truly isomorphical solid solutions and anomalous mixed crystals, it was shown that mendelevium co-crystallizing with NaCl is in its monovalent state. Besides, it was concluded that up to 1.5 M chloride concentration the monovalent mendelevium does not form stable chloride complexes in water-ethanol solutions. (author)