Vibrational spectra and phase transitions in columnar M[M′III(SO4)3] compounds

✍ Scribed by Claude Bremard; Jacky Laureyns; Francis Abraham

• Publisher: John Wiley and Sons
• Year: 1986
• Tongue: English
• Weight: 663 KB
• Volume: 17
• Category: Article
• ISSN: 0377-0486
• DOI: 10.1002/jrs.1250170505

✦ Synopsis

Compounds of general formula M~[M''"(SO,

),] exhibit a columnar structure and, at room temperature, belong to the Cz,,, Cii and C!= symmetry space groups with, respectively, M'=Tl. M""=ln; M'=Tl, MrlIL=Fe; and MI = Cs, M'"'= Fe.

The Raman spectra of powder samples have been recorded in the temperature range 77-600 K. These vibrational studies indicate the role played by the SO, groups and M' cations in the phase transitions. All the compounds follow a space group phase sequence in accordance with the general point group relationship 2 / m +& 3m +3m.