Collect. Czech. Chem. Commun. 1996, 61, 1295-1306

Crystal Structure, Thermoanalytical Properties and Infrared Spectra of Double Magnesium Selenates

Zdeněk Mička, Lucie Prokopová, Ivana Císařová and David Havlíček

Department of Inorganic Chemistry, Charles University, 128 40 Prague 2, Czech Republic


Magnesium selenates double salts K2Mg(SeO4)2.6H2O, Rb2Mg(SeO4)2.6H2O, Cs2Mg(SeO4)2.6H2O, and (NH4)2Mg(SeO4)2.6H2O have been studied by means of X-ray diffraction methods, thermoanalytical methods, and infrared spectroscopy. The basic building units of these compounds are slightly deformed tetrahedra of selenate anions and octahedra of hexaaquamagnesium(II) cations interconnected by a system of hydrogen bonds. The investigation of IR spectra has been used in the discussion of X-ray diffraction results in the field of description of the hydrogen bond system and deformation of the basic polyhedra of selenate anion and hexaaquamagnesium cation. The thermoanalytical studies are used in evaluating the effects of hydrogen bonds and polarization influence of M+ cations on thermal stability of the compounds studied.

Keywords: Double magnesium selenates with potassium, rubidium, caesium, and ammonium; X-Ray diffraction analysis; Infrared spectra; Thermoanalytical properties.