Skip to main content
SpringerLink
Log in

The fluorination of scheelite with ammonium bifluoride

  • Published:
Journal of thermal analysis Aims and scope Submit manuscript

Abstract

The interaction of scheelite with ammonium bifluoride was studied. It was shown that sheelite reacts with NH4HF2 at room temperature, in contrast with tungstic oxide and other tungsten compounds. Two complexes are formed (NH4)3WO3F3 and the previously unknown (NH4)2WO3F2. The compounds obtained were fluorinated to (NH4)3WO2F5 (endothermic peaks at 170° and 90°C, respectively).

Cubic monocrystals of (NH4)3WO2F5 were obtained. The cubic form is unstable and underwent a lattice transformation at room temperature to the more stable tetragonal form, which was transformed reversibly into the cubic form at 140°C. The thermal decomposition of (NH4)2WO3F2 was studied.

Zusammenfassung

Es wird die Wechselwirkung von Scheelit und Ammoniumhydrogenfluorid untersucht. Im Gegensatz zu Wolframoxid und anderen Wolframverbindungen geht Scheelit mit Ammoniumhydrogenfluorid bei Raumtemperatur eine chemische Reaktion ein, wobei zwei verschiedene Komplexe gebildet werden: (NH4)WO3F3 und der bisher unbekannte Komplex (NH4)2WO3F2. Die erhaltenen Verbindungen werden zu (NH4)3WO2F5 fluoriert (endotherme Peaks bei 170° bzw. 90°C).

Man erhält die kubischen Einkristalle (NH4)3WO2F5. Die unstabile kubische Form wandelte sich bei Raumtemperatur in die stabilere tetragonale Form um, die bei 140°C reversibel wieder in die kubische Form überführt werden kann.

Es wird weiterhin die thermische Zersetzung von (NH4)2WO3F2. untersucht.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  1. N. A. Veleshko, E. G. Rakov and G. A. Jagodin, Proc. of the Mendeleev Moscow Chemical Technological Institute, 97 (1977) 30.

    Google Scholar 

  2. L. K. Marinina, E. G. Rakov, B. V. Gromovet al, ibid, 67 (1970) 83.

    Google Scholar 

  3. M. A. Porai-Koshits and L. O. Avtovmjan, Crystallochemistry and Stereochemistry of the molybden coordination compounds, Nauka, Moscow 1974.

    Google Scholar 

  4. A. A. Opalovsky, S. S. Batsanov and L. M. Kuznetsova, Izvestija of Ac. Sci. USSR, ser. chem., (1963) 2110.

  5. A. A. Opalovsky, L. M. Kuznetsova and S. S. Batsanov, Izvestija Sibirskogo otdelenija Ac. Sci. USSR, 9 (1962) 46.

    Google Scholar 

  6. P. S. Gordienko, S. B. Bulanova, E. I. Melnichenko and S. V. Fadeev, Collection articles “Thermal analysis and Phase equilibrium”, Perm, 1983, p. 61.

  7. E. G. Rakov, E. I. Melnichenko and S. A. Polyshcuk, Russian J. Inorg. Chem., 1 (1983) 249.

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Institute of Chemistry, Far East Branch of Russian Academy of Sciences, Vladivostok, RF

    N. M. Laptash, E. I. Melnichenko, S. A. Polyshchuk & T. A. Kaidalova

Authors
  1. N. M. Laptash
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. E. I. Melnichenko
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. S. A. Polyshchuk
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. T. A. Kaidalova
    View author publications

    You can also search for this author in PubMed Google Scholar

Rights and permissions

Reprints and permissions

About this article

Cite this article

Laptash, N.M., Melnichenko, E.I., Polyshchuk, S.A. et al. The fluorination of scheelite with ammonium bifluoride. Journal of Thermal Analysis 38, 2335–2341 (1992). https://doi.org/10.1007/BF02123986

Download citation

  • Received:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF02123986

Keywords

Search

Navigation