Hostname: page-component-78c5997874-94fs2 Total loading time: 0 Render date: 2024-11-10T08:44:57.021Z Has data issue: false hasContentIssue false

Crystal chemistry and location of hydrogen atoms in prehnite

Published online by Cambridge University Press:  05 July 2018

T. A. Detrie
Affiliation:
Crystallography Laboratory, Department of Geosciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
N. L. Ross
Affiliation:
Crystallography Laboratory, Department of Geosciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
R. J. Angel
Affiliation:
Crystallography Laboratory, Department of Geosciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
M. D. Welch
Affiliation:
Department of Mineralogy, The Natural History Museum, Cromwell Road, London SW7 5BD, UK

Abstract

The structure of prehnite Ca2Al(AlSi3O10)(OH)2, including H positions, has been determined by a combination of single-crystal X-ray diffraction and neutron powder diffraction on four natural samples. The symmetry of the average structure with Al/Si disordered at the T2 siteis Pncm. However, for four of the crystals studied, numerous violations of the n- and c-glide reflection conditions indicate lower symmetry corresponding to space groups P2cm and P2/n and Al-Si ordered structures, possibly as domains of different symmetries and ordering within a single crystal. Time-of-flight neutron powder diffraction was carried out on a sample from Mali at 293 K and 2 K. The structure was refined in space group Pncm by Rietveld analysis. Although it was not possible to locate the missing H using the 293 K neutron data, these data were used to refine the H position located approximately by single-crystal XRD and to refine Uiso. For the 2 K neutron powder diffraction data, H was located directly by difference-Fourier synthesis and its refined position found to be in close agreement with that obtained by the combined XRD/neutron 293 K dataset.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2008

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Akasaka, M., Hashimoto, H., Makino, K. and Hino, R. (2003) 57Fe Mossbauer and X-ray Rietveld studies of ferrian prehnite from Kouragahana, Shimane Peninsula, Japan. Journal of Mineralogical and Petrological Sciences, 98, 3140.CrossRefGoogle Scholar
Akizuki, M. (1987) Al,Si order and the internal texture of prehnite. The Canadian Mineralogist, 25, 707716.Google Scholar
Angel, R.J., Carpenter, M.A. and Finger, L.W. (1990) Structural variation associated with the compositional variation and order-disorder behavior in anorthite-rich feldspars. American Mineralogist, 75, 150162.Google Scholar
Artioli, G., Quartieri, S. and Deriu, A. (1995) Spectroscopic data on coexisting prehnite-pumpell-yite and epidote-pumpellyite. The Canadian Mineralogist, 33, 6775.Google Scholar
Aumento, F. (1968) The space group of prehnite. The Canadian Mineralogist, 9, 485492.Google Scholar
Balic-Zunic, T., Scavnicar, S. and Molin, G. (1990) Crystal structure of prehnite from Komiza. European Journal of Mineralogy, 2, 731734.CrossRefGoogle Scholar
Baur, W.H., and Hofmeister, W. (1990) Prehnite: structural similarity of the monoclinic and orthor-hombic polymorphs and their Si/Al ordering. Journal of Solid State Chemistry, 86, 330333.CrossRefGoogle Scholar
Berry, AJ. and James, M. (2002) Refinement of hydrogen positions in natural chondrodite by powder neutron diffraction: implications for the stability of humite minerals. Mineralogical Magazine, 66, 441449.CrossRefGoogle Scholar
Farrugia, LJ. (1999) WinGX suite for small-molecule single-crystal crystallography. Journal of Applied Crystallography, 32, 837838.CrossRefGoogle Scholar
Geisinger, K.L., Gibbs, G.V. and Navrotsky, A. (1985) A molecular orbital study of bond length and angle variations in framework silicates. Physics and Chemistry of Minerals, 11, 266283.CrossRefGoogle Scholar
Larson, A.C. and Von Dreele, R.B. (2000) GSAS-General Structure Analysis System. Los Alamos National Laboratory, LAUR-86—748.Google Scholar
Lowenstein, W. (1954) The distribution of aluminum in the tetrahedra of silicates and aluminates. American Mineralogist, 39, 9296.Google Scholar
Momma, K. and Izumi, F. (2008) VESTA: a three-dimensional visualization system for electronic and structural analysis. Journal of Applied Crystallography, 41, 653658.CrossRefGoogle Scholar
Nuffield, E.W. (1943) Prehnite from Ashcroft, British Columbia. University of Toronto Studies, 48, 4964.Google Scholar
Papike, JJ. and Zoltai, T. (1967) Ordering of tetrahedral aluminum in prehnite Ca2(AlFe+ )[Si3A10io](OH)2 . American Mineralogist, 52, 974984.Google Scholar
Peng, S.-T., Chou, K.-D. and Tang, Y.-C. (1959) The structure of prehnite. Ada Chemistry Sinica, 25, 5663.Google Scholar
Phillips, M.W. and Ribbe, P.H. (1973) The variation of tetrahedral bond lengths in sodic plagioclase feldspars. Contributions to Mineralogy and Petrology, 39, 327339.CrossRefGoogle Scholar
Post, J.E., Heaney, P.J., von Dreele, R.B. and Hanson, J.C. (2003) Neutron and temperature-resolved synchrotron powder diffraction study of akaganeite. American Mineralogist, 88, 782788.CrossRefGoogle Scholar
Preisinger, A. (1965) Prehnit - ein neuer Schichtsilikattyp. Tschermaks Mineralogische und Petrographische Mitteilungen, 10, 491504.CrossRefGoogle Scholar
Salvado, M.A., Pertierra, P., Garcia-Granda, S., Garcia, J.R., Rodriguez, J. and Fernandez-Diaz, M.T. (1996) Neutron powder diffraction study of ot-Ti(HPO4)2.H2O and a-Hf(HPO4)2.H2O; H-atom positions. Ada Crystallographica B, 52, 896898.Google Scholar
Sheldrick, G.M. (2008) A short history of SHELX. Ada Crystallographica A, 64, 112122.Google Scholar
Traube, H. (1894) Uber die pyroelecktrischen Eigenschaften und die Krystallform des Prehnits. Neues Jahrbuch fur Mineralogie, 9, 134146.Google Scholar
Welch, M.D., Marshall, W.G., Ross, NX. and Knight, K.S. (2002) H positions in leucophoenicite, Mn7Si3O12(OH)2: A close relative of the hydrous B phases. American Mineralogist, 87, 154159.CrossRefGoogle Scholar