Advertisement

Physics and Chemistry of Minerals

, Volume 21, Issue 8, pp 539–545 | Cite as

Low temperature dynamics of molecular H2O in bassanite, gypsum and cordierite investigated by high resolution incoherent inelastic neutron scattering

  • Björn WinklerEmail author
  • Bernard Hennion
Article

Abstract

The low temperature dynamics of molecular H2O has been studied in gypsum (CaSO4·2H2O), bassanite (CaSO4·0.5 H2O) and cordierite (Mg2Al4Si5O18·H2O) using neutron spectroscopy. In gypsum, where the H2O is structurally bound and the protons can be located in diffraction studies, inter- and intramolecular motions of the H2O and SO4 groups have been observed. In bassanite, two broad bands in a spectrum recorded at 150 K imply that at this temperature the H2O is dynamically disordered and a static description of the room temperature structure is inappropriate. At low temperatures the H2O molecules order, and at 3 K the spectrum consists of a number of sharp bands. In synthetic, alkali-free hydrous cordierite the H2O molecules are dynamically disordered. This has been shown by earlier NMR and room temperature quasielastic neutron scattering studies, and has been confirmed here by low temperature (50 K) quasielastic neutron scattering. A temperature decrease down to 3 K induces only gradual changes in the inelastic spectrum, and the three bands which we have observed are significantly broadened. It is therefore concluded, that the dynamic disorder persists even down to 3 K. This is in agreement with results from NMR spetroscopic experiments for beryl. High resolution time-of-flight spectra obtained at 3 K exclude tunneling.

Keywords

Gypsum Cordierite CaSO4 Inelastic Neutron Scattering Bassanite 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Abriel W, Nesper R (1993) Bestimmung der Kristallstruktur von CaSO4(H2O)0.5 mit Röntgenbeugungsmethoden und mit Potentialprofil-Rechnungen. Z Kristallogr 205:99–113Google Scholar
  2. Aines RD, Rossman GR (1984) The high temperature behavior of water and carbon dioxide in cordierite and beryl. Amer Mineral 69:319–327Google Scholar
  3. Atoji M, Rundle RE (1958) Neutron diffraction study of gypsum, CaSO4·2H2O. J Chem Phys 29:1306–1311Google Scholar
  4. Bee M (1988) Quasielastic neutron scattering, 437 p. Adam Hilger, BristolGoogle Scholar
  5. Boutin H, Safford GJ, Danner HR (1964) Low frequency motions of H2O molecules in crystals. J Chem Phys 40:2670–2679Google Scholar
  6. Carey JW (1993) The heat capacity of hydrous cordierite above 295 K. Phys Chem Minerals 19:578–583Google Scholar
  7. Carson DG, Rossman GR, Vaughan RW (1982) Orientation and motion of water molecules in cordierite: a proton nuclear magnetic resonance study. Phys Chem Minerals 8:14–19Google Scholar
  8. Farrel EF, Newnham RE (1967) Electronic and vibrational absorption spectra in cordierite. Amer Mineral 51:1068–1087Google Scholar
  9. Fuess H, Stuckenschmidt E, Schweiss BP (1986) Inelastic neutron scattering studies of water in natural zeolites. Ber Bunsenges für Physik und Chemie 90:417–421Google Scholar
  10. Johannes W, Schreyer W (1981) Experimental introduction of CO2 and H2O into Mg-cordierite. Amer J Sci 281: 299–317Google Scholar
  11. Lager GA, Armbruster T, Rotella FJ, Jorgensen JD, Hinks DG (1984) A crystallographic study of the low temperature dehydration products of gypsum, CaSO4-2H2O: hemihydrate CaSO4· 0.50H2O, and γ-CaSO4. Amer Mineral 69:910–918Google Scholar
  12. Line CMB, Winkler B, Dove MX (1994) Quasielastic incoherent neutron scattering study of the rotational dynamics of the water molecules in analcime. Phys Chem Minerals, in pressGoogle Scholar
  13. Pare X, Ducros P (1964) Etude par resonance magnetique nucleaire de l'eau dans le beryl. Bull Soc Francaise Mineral Crystallogr 87:429–433Google Scholar
  14. Pedersen BF, Semmingsen D (1982) Neutron diffraction refinement of the structure of gypsum, CaSO4-2H2O. Acta Crystallogr 838:1074–1077Google Scholar
  15. Penfold J, Tomkinson J (1986) The ISIS time focused crystal analyser spectrometer, TFXA. Rutherford Appleton Publication RAL-86-019Google Scholar
  16. Putnis A, Winkler B, Fernandez-Diaz L (1990) In situ IR spectroscopic and thermogravimetric study of the dehydration of gypsum. Mineral Magaz 54:123–128Google Scholar
  17. Rossman GR (1988) Vibrational spectroscopy of hydrous components. In : Hawthorne FC (ed) Spectroscopic methods in mineralogy and geology. Rev Mineral 18:193–206Google Scholar
  18. Ryskin YI (1974) The vibrations of protons in minerals: hydroxyl, water and ammonium. In: Farmer VC (ed) The infrared spectra of minerals. Mineralogical Society, London, 137–182, 539 ppGoogle Scholar
  19. Seidl V, Knop O, Falk M (1969) Infrared studies of water in crystalline hydrates: gypsum, CaSO4·2H2O. Canad J Chem 47: 1361–1368Google Scholar
  20. Stuckenschmidt E, Fuess H, Stockmeyer R (1988) Water motion in Harmotone — studied by incoherent inelastic and quasielastic neutron scattering. Ber Bunsenges für Physik und Chemie 92:1083–1089Google Scholar
  21. Strens RG (1974) The common chain, ribbon, and ring silicates. In: Farmer VC (ed) The infrared spectra of minerals. Mineralogical Society, London, 305–330, 539 ppGoogle Scholar
  22. Sugitani Y, Nagashima K, Fujiwara S (1966) The NMR analysis of the water of crystallization in beryl. Bull Chem Soc Japan 39:672–674Google Scholar
  23. Winkler B, Coddens G, Hennion B (1994a) Movement of channel water in cordierite observed with quasielastic neutron scattering. Amer Mineral, in pressGoogle Scholar
  24. Winkler B, Milman V, Payne MC (1994b) Orientation, location and total energy of hydration of channel H2O in cordierite investigated by ab initio total energy calculations. Amer Mineral 79:200–204Google Scholar

Copyright information

© Springer-Verlag 1994

Authors and Affiliations

  1. 1.Mineralogisch-Petrographisches Institut der Christian-Albrechts UniversitätKielGermany
  2. 2.Laboratoire Leon Brillouin, CEN SaclayGif-sur-YvetteFrance

Personalised recommendations