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In situ HT‐XRD Study on the Formation of Hexagonal Ammonium Tungsten Bronze by Partial Reduction of Ammonium Paratungstate Tetrahydrate
Author(s) -
Szilágyi Imre Miklós,
Hange Ferenc,
Madarász János,
Pokol György
Publication year - 2006
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200500875
Subject(s) - tetrahydrate , tungsten , chemistry , x ray photoelectron spectroscopy , bronze , inorganic chemistry , ammonium , powder diffraction , nuclear chemistry , crystallography , crystal structure , metallurgy , materials science , chemical engineering , organic chemistry , engineering
Hexagonal ammonium tungsten bronze, (NH 4 ) 0.33– x WO 3– y , is a possible constituent of the intermediate “tungsten blue oxide” in non‐sag (NS) tungsten production and a material of chromogenic and sensor interest. Its formation has been studied by in situ high‐temperature powder X‐ray diffraction (HT‐XRD) accompanied by semiquantitative phase analysis through the partial thermal reduction of ammonium paratungstate tetrahydrate, (NH 4 ) 10 [H 2 W 12 O 42 ] · 4H 2 O, in flowing 10 % H 2 /He. The effect of the heating program on the formation of the title compound has been discussed. Highly crystalline, monophasic hexagonal ammonium tungsten bronze prepared by partial reduction of ammonium paratungstate tetrahydrate has been characterised by high‐precision powder XRD, X‐ray photoelectron spectroscopy (XPS), chemical analysis and solid‐state 1 H NMR spectroscopy ( 1 H‐MAS‐NMR). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)