Polyhalite and its analogous triple salts

Autor:	Daniela Freyer, Georgia Wollmann, Wolfgang Voigt
Rok vydání:	2008
Předmět:	Ionic radius Chemistry Polyhalite General Chemistry engineering.material Triclinic crystal system Ion Crystallography symbols.namesake Octahedron engineering symbols Molecule Raman spectroscopy Powder diffraction
Zdroj:	Monatshefte für Chemie - Chemical Monthly. 139:739-745
ISSN:	1434-4475 0026-9247
Popis:	Polyhalite (K2SO4 · MgSO4 · 2CaSO4 · 2H2O) and analogue triple salts, where Mg2+ is substituted by Mn2+, Fe2+, Co2+, Ni2+, Cu2+ and Zn2+, have been synthesized. The salts were characterized by thermal analysis, Raman spectroscopy and X-ray powder diffraction. Diffraction patterns and Raman spectra resemble those of natural polyhalite, except K2SO4 · CuSO4 · 2CaSO4 · 2H2O. The latter corresponds to the mineral leightonite, which is structurally different. For polyhalite analogues the cell parameters of the triclinic unit cell have been determined from the powder diffraction patterns. The length of the unit cell vectors varies regularly with the ionic radius of the substituted ion M 2+ and is explained by changes in the extension of the coordination octahedron of M 2+. Thereby increasing distances of the coordinated water molecules at M 2+ parallel with decreasing dehydration temperatures of the corresponding polyhalite.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::18913e8336d0c9d17a49a0d94a819f42 https://doi.org/10.1007/s00706-007-0835-7 Zobrazit plný text záznamu Full text from SpringerLink