Premium
New Structure Type among Octahydrated Rare‐Earth Sulfates, β‐Ce 2 (SO 4 ) 3 ·8H 2 O, and a new Ce 2 (SO 4 ) 3 ·4H 2 O Polymorph
Author(s) -
Casari Barbara M.,
Langer Vratislav
Publication year - 2007
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.200700003
Subject(s) - cerium , crystallography , crystal structure , sulfate , chemistry , lanthanide , thermal decomposition , homoleptic , group (periodic table) , space group , inorganic chemistry , x ray crystallography , metal , ion , diffraction , physics , organic chemistry , optics
Syntheses, crystal structures and thermal behavior of two new hydrated cerium(III) sulfates are reported, Ce 2 (SO 4 ) 3 ·4H 2 O ( I ) and β‐Ce 2 (SO 4 ) 3 ·8H 2 O ( II ), both forming three‐dimensional networks. Compound I crystallizes in the space group P 2 1 / n . There are two non‐equivalent cerium atoms in the structure of I , one nine‐ and one ten‐fold coordinated to oxygen atoms. The cerium polyhedra are edge sharing, forming helically propagating chains, held together by sulfate groups. The structure is compact, all the sulfate groups are edge‐sharing with cerium polyhedra and one third of the oxygen atoms, belonging to sulfate groups, are in the S–Oμ 3 –Ce 2 bonding mode. Compound II constitutes a new structure type among the octahydrated rare‐earth sulfates which belongs to the space group Pn . Each cerium atom is in contact with nine oxygen atoms, these belong to four water molecules, three corner sharing and one edge sharing sulfate groups. The crystal structure is built up by layers of [Ce(H 2 O) 4 (SO 4 )] n n+ held together by doubly edge sharing sulfate groups. The dehydration of II is a three step process, forming Ce 2 (SO 4 ) 3 ·5H 2 O, Ce 2 (SO 4 ) 3 ·4H 2 O and Ce 2 (SO 4 ) 3 , respectively. During the oxidative decomposition of the anhydrous form, Ce 2 (SO 4 ) 3 , into the final product CeO 2 , small amount of CeO(SO 4 ) as an intermediate species was detected.