Thermal Decomposition of Ammonium Hexafluorovanadate (III)

• K\={o}yama K\={o}ichir\={o}

  Department of Materials Science, Himeji Institute of Technology

• Hashimoto Yasuhiko

  Department of Materials Science, Himeji Institute of Technology

抄録

In order to establish the conditions for the preparation of pure vanadium trifluoride, VF₃, from ammonium hexafluorovanadate (III), (NH₄)₃VF₆, the preparation of (NH₄)₃VF₆ and its thermal decomposition have been studied by means of thermogravimetric analysis, differential thermal analysis, and X-ray diffraction analysis. Ammonium hexafluorovanadate can be prepared by heating a mixture of V₂O₃ and NH₄HF₂ in the molar ratio of 1:8–1:12 at 185–250°C in an inert atmosphere. Vanadium trifluoride can be prepared by heating (NH₄)₃VF₆ at 600–700°C in an inert atmosphere. The mechanism of thermal decomposition of (NH₄)₃VF₆ is as follows:<BR>(NH₄)₃VF₆ → α → β → γ → VF₃,<BR>in which α is believed to be ammonium pentafluorovanadate (III), (NH₄)₂VF₅, and β has been found to be a nonstoichiometric compound with the chemical formula of (NH₄F)_1−x·VF₃, 0≤x≤∼0.3, which belongs to a tetragonal system. The lattice parameters of ammonium tetrafluorovanadate (III), NH₄VF₄(NH₄F·VF₃), oare a=7.58, c=6.36, c⁄a=0.839. The composition of γ is very near to that of VF₃ and γ contains a small amount of NH₄F (about 0.1–1.5 wt% NH₄).

収録刊行物

• Transactions of the Japan Institute of Metals

  Transactions of the Japan Institute of Metals 17 (5), 287-293, 1976

  社団法人 日本金属学会

キーワード

• General Engineering

詳細情報

• CRID: 1390001205118824192
• NII論文ID: 130003485480
• DOI: 10.2320/matertrans1960.17.287
• COI: 1:CAS:528:DyaE28XksFGru74%3D
• ISSN: 24324701
• ISSN: 00214434
• Web Site: https://www.jstage.jst.go.jp/article/matertrans1960/17/5/17_5_287/_pdf
• 本文言語コード: en
• データソース種別:
  • JaLC
  • Crossref
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可