Hostname: page-component-586b7cd67f-l7hp2 Total loading time: 0 Render date: 2024-11-24T06:31:01.094Z Has data issue: false hasContentIssue false

Holtite, (Si2.25Sb0.75)B [Al6(Al0.43Ta0.270.30) O15 (O,OH)2.25]: crystal structure and crystal chemistry

Published online by Cambridge University Press:  05 July 2018

B. F. Hoskins
Affiliation:
University of Melbourne, Parkville, Melbourne, Australia
W. G. Mumme
Affiliation:
CSIRO, Division of Mineral Products, P.O. Box 124, Port Melbourne, Australia
M. W. Pryce
Affiliation:
Government Chemical Laboratories, Perth, Western Australia

Abstract

Holtite, (Si2.25Sb0.75)B[Al6(Al0.43Ta0.270.30)O15(O,OH)2.25], is orthorhombic a = 4.6914(5), b = 11.896(2), c = 20.383(4)Å, space group Pnma. Full-matrix least-squares refinement yielded a final R = 0.030, for 1664 reflections with I ⩾ 3σ(I). Its crystal structure is closely related to that of dumortierite, but with the difference that extensive substitution of Si by Sb occurs in holtite. SbO3 triangular pyramids replace the SiO4 tetrahedra arranged around the inside edge of the hexagonally shaped tunnels which are the feature of the dumortierite and holtite structures. Associated with these replacements is the replacement of Al by Ta in the octahedral site centred in these tunnels, and the development of vacancies in this metal site and its attached oxygens.

Type
Mineralogy
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1989

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

Fleischer, M. (1983) Glossary of Mineral Species, 4th ed., Mineralogical Record, Tucson.Google Scholar
Golovastikov, N. I. (1965) The crystal structure of dumortierite. Soviet Phys. Dokl. 10, 493-5.Google Scholar
International Tables for X-ray Crystallography (1974) Volume 4(b) p. 99: Kynoch Press.Google Scholar
Losert, J. (1956) Dumortierite from the pegmatites and migmatites in the region of Kutna Hora [English summary]. Roz. Cesk. Acad. Ved. 66, 1-48.Google Scholar
Main, P., Hull, S. E., Lessinger, L., Germain, G., Declereq, J-P. and Woolfson, M. M. (1978) MULTAN78, a system ofcomputerprograrns for the automatic solution of crystal structures from X-ray diffraction data. University of York, York, England.Google Scholar
Moore, P. M. and Araki, T. (1978) Dumortierite, SiB[Al6.750.25O17.25, (OH)0.75]: a detailed structure analysis. Neues Jahrb. Mineral. Abh. 132, 231-41.Google Scholar
Murty, T. V. V. G. R. K. (1971) A study of Alwar Series near Shahpura, Jaipur (India). Stud. Earth Sci. (West Commem. Vol.), Univ. Saugur, 353-8.Google Scholar
Pryce, M. W. (1971) Holtite: a new mineral allied to dumortierite. Mineral. Mag. 38, 21-5.CrossRefGoogle Scholar
Sheldrick, G. M. (1976) SHELX-76. Program for crystal structure determination. University of Cambridge, Cambridge, England.Google Scholar
Voloshin, A. V., Gordienk, V. V., Gelman, E. M., Zorina, M. L., Elina, N. A., Kulchitsaya, E. A., Menshikov, U. P., Polejaeva, L. I., Rijova, R. I., Sokolov, P. B. and Utochkina, G. I. (1976) Holtite (first occurrence in U.S.S.R) and its interrelations with other minerals of tantalum in rare metal pegmatite (in Russian). New Minerals and First Occurrences in U.S.S.R. 3, Part 106, 337-47.Google Scholar