title: Raman spectroscopic study of crystallization from solutions containing MgSO4 and Na2SO4: Raman spectra of double salts.
abstract: Mg(2+), Na(+), and SO(4)(2-) are common ions in natural systems, and they are usually found in water bodies. Precipitation processes have great importance in environmental studies because they may be part of complex natural cycles; natural formation of atmospheric particulate matter is just one case. In this work, Na(2)Mg(SO(4))(2)·5H(2)O (konyaite), Na(6)Mg(SO(4))(4) (vanthoffite), and Na(12)Mg(7)(SO(4))(13)·15H(2)O (loeweite) were synthesized and their Raman spectra reported. By slow vaporization (at 20 °C and relative humidity of 60-70%), crystallization experiments were performed within small droplets (diameter ≤ 1-2 mm) of solutions containing MgSO(4) and Na(2)SO(4), and crystal formations were studied by Raman spectroscopy. Crystallization of Na(2)Mg(SO(4))(2)·4H(2)O (bloedite) was observed, and the formation of salt mixtures was confirmed by Raman spectra. Bloedite, konyaite, and loeweite, as well as Na(2)SO(4) and MgSO(4)·6H(2)O, were the components found to occur in different proportions. No crystallization of Na(6)Mg(SO(4))(4) (vanthoffite) was observed under the crystallization condition used in this study.
authors.affiliation: Institut für Physikalische Chemie, Friedrich-Schiller-Universität Jena, D-07743 Jena, Germany.
authors.forename: Paul
authors.initials: P
authors.lastname: Vargas Jentzsch
authors.forename: Bernd
authors.initials: B
authors.lastname: Kampe
authors.forename: Petra
authors.initials: P
authors.lastname: Rösch
authors.forename: Jürgen
authors.initials: J
authors.lastname: Popp