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Solid state vibrational spectroscopy. 8 —A thermochemical and vibrational spectroscopic study of the solid state thermal decompositions of alkali metal peroxydisulphates
Author(s) -
Cleaver Kevin D.,
Davies J. Eric D.
Publication year - 1980
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1250090607
Subject(s) - thermogravimetric analysis , raman spectroscopy , differential scanning calorimetry , alkali metal , chemistry , thermal decomposition , analytical chemistry (journal) , stoichiometry , infrared spectroscopy , thermal analysis , phase (matter) , spectroscopy , endotherm , inorganic chemistry , thermal , thermodynamics , organic chemistry , quantum mechanics , physics , optics
The solid state thermal decompositions of the alkali metal peroxydisulphates M 2 [S 2 O 8 ], M = Na, K, Rb, Cs, have been studied using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), in situ high temperature Raman spectroscopic studies, and by recording the infrared and Raman spectra of the products formed when the salts are heated to various temperatures. In addition to detecting the exotherm associated with the decomposition of peroxydisulphate to pyrosulphate and the endotherm associated with the fusion of pyrosulphate, the DSC study detected previously unreported solid state phase changes of Cs 2 [S 2 O 8 ] and K 2 [S 2 O 7 ]. These phase changes are also detectable using Raman spectroscopy. The TGA study indicates the formation of an intermediate in the decomposition of pyrosulphate to sulphate, but it is not possible to determine its stoichiometry from the TGA study.