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Novel Metastable Structures of WO 3 , MoO 3 and W 1‐ x Mo x O 3 Obtained by the Deintercalation of Layered Amine Adducts
Author(s) -
Ayyappan S.,
Subbanna G. N.,
Rao C. N. R.
Publication year - 1995
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.19950010305
Subject(s) - metastability , adduct , amine gas treating , octahedron , chemistry , triethylamine , pyridine , inorganic chemistry , metal , crystallography , crystal structure , medicinal chemistry , organic chemistry
Deintercalation of amines from the layered amine adducts of WO 3 , MoO 3 and W 1‐ x Mo x O 3 has been employed as a soft chemical route to produce unusual metastable structures of the oxides. After the adducts of WO 3 , MoO 3 and W 1– x Mo x O 3 ( x = 0.25, 0.5, 0.75) with amines such as triethylamine (TEA), pyridine, n ‐butylamine and n ‐octylamine had been characterized, deintercalation was carried out thermally as well as by acid leaching. Thermal deintercalation yielded novel metastable structures of WO 3 and MoO 3 that were significantly different from the stable forms, which contain distorted metal‐oxygen octahedra. Thus, ReO 3 ‐type cubic WO 3 was obtained by the thermal deintercalation of WO 3 · 0.5 TEA. Acid leaching of the amines gave metastable phases of WO 3 , MoO 3 and W 1‐ x Mo x O 3 , which were different from those obtained thermally. All the metastable phases transformed to the corresponding stable forms at higher temperatures.