Jump to ContentJump to Main Navigation
Show Summary Details
More options …

American Mineralogist

Journal of Earth and Planetary Materials

Ed. by Baker, Don / Xu, Hongwu / Swainson, Ian


IMPACT FACTOR 2017: 2.645

CiteScore 2017: 2.31

SCImago Journal Rank (SJR) 2017: 1.440
Source Normalized Impact per Paper (SNIP) 2017: 1.059

Online
ISSN
1945-3027
See all formats and pricing
More options …
Volume 86, Issue 10

Issues

Crystal structure of a new (21)-clinopyribole synthesized at high temperature and pressure

Hexiong Yang
  • Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, N.W., Washington, D.C. 20015-1305, U.S.A.
  • Jet Propulsion Laboratory, Mail Stop 183-301, 4800 Oak Grove Drive, Pasadena, CA 91109-8099
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Jürgen Konzett
  • Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, N.W., Washington, D.C. 20015-1305, U.S.A.
  • Institut für Mineralogie und Petrographie, Universität Innsbruck, Innrain 52, A-6020 Innsbruck, Austria
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Charles T. Prewitt
  • Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, N.W., Washington, D.C. 20015-1305, U.S.A.
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
Published Online: 2015-03-26 | DOI: https://doi.org/10.2138/am-2001-1013

Abstract

A (21)-clinopyribole with the composition K1.10Na2.32Ca1.52Mg5.85Al1.23Si12.04O34(OH)2 has been syn­thesized at 10 GPa and 1250 °C in a multi-anvil apparatus. The unit-cell parameters are a = 9.8390(9), b = 26.6471(6), c = 5.2665(5) Å, β = 106.25(5)°, and V = 1325.6(4) Å3. The structure (space group A2/m) consists of an alternating arrangement of single- and double-chain silicate slabs along the b axis, with a + + + + configuration. This phase possesses all the features predicted by Veblen and Burnham (1978b) for a mixed-chain silicate intermediate between pyroxenes and amphiboles. The single-chain portion of the structure corresponds to a clinopyroxene with the omphacite composition Di55Jd45, whereas the double chain portion is essentially a potassic richterite. The MS2 cation in the single-chain portion occupies a coordination environment that is similar to the M4 site in richterite, whereas the MD4 cation coordination in the double-chain portion is comparable to the M2 site in C2/c omphacite. The observed unit-cell volume is 1.5% smaller than the equivalent mixture of Di55Jd45 + richterite, accounting, in part, for its high-pressure stability relative to its pyroxene and amphibole components.

About the article

Received: 2000-11-10

Accepted: 2001-06-11

Published Online: 2015-03-26

Published in Print: 2001-10-01


Citation Information: American Mineralogist, Volume 86, Issue 10, Pages 1261–1266, ISSN (Online) 1945-3027, ISSN (Print) 0003-004X, DOI: https://doi.org/10.2138/am-2001-1013.

Export Citation

© 2015 by Walter de Gruyter Berlin/Boston.

Comments (0)

Please log in or register to comment.
Log in