A new niobium tungsten oxide as a result of an in situ reaction in a gas reaction cell microscope

Journal Article · Mon Feb 15 04:00:00 EST 1999 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1006/jssc.1998.8062· OSTI ID:349911

Sayagues, M J; Hutchison, J L ^[1]; Krumeich, F ^[2]

---

1. Univ. of Oxford (United Kingdom). Dept. of Materials
2. ETH Zuerich (Switzerland). Lab. of Inorganic Chemistry

Nb{sub 7}W{sub 10}O{sub 47} was heated by an electron beam in a gas atmosphere (O{sub 2}, He, or H{sub 2}) of the gas reaction cell installed in a JEOL 4000 EX high-resolution transmission electron microscope (HRTEM). This treatment generated a new niobium tungsten oxide (Nb, W){sub 12}O{sub 32}, crystallizing in a {radical}(2a) {times} {radical}(2a) superstructure of the tetragonal tungsten bronze (TTB) type. While the TTB substructure remains unaltered by this reaction, the proportion of pentagonal tunnels occupied with metal-oxygen strings has increased. The simultaneous occupation of all four pentagonal tunnels around a central square of octahedra is the characteristic structural feature of (Nb, W){sub 12}O{sub 32}. This arrangement is observed here for the first time in the ternary system Nb/W/O. During the reaction, a part of the tungsten oxide is etched away and condenses as small particles near the irradiated crystallite.

• Sponsoring Organization: Swiss National Science Foundation, Bern (Switzerland)
• OSTI ID: 349911
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 1 Vol. 143; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
40 CHEMISTRY
CRYSTAL STRUCTURE
DATA
HYDROGEN
IN-SITU PROCESSING
NIOBIUM OXIDES
OXIDATION
OXYGEN
REDUCTION
TRANSMISSION ELECTRON MICROSCOPY
TUNGSTEN OXIDES