The crystal structure of CaSiO3-walstromite, a special isomorph of wollastonite-II
The crystal structure of CaSiO -walstromite has been solved and refined by a data set collected from an inclusion in a diamond single crystal (1135 observed reflections, Mo , Nonius CAD4, = 3.46). The crystal structure is almost identical to that of walstromite (Ca BaSi ). The replacement of Ba by C...
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Published in | Zeitschrift für Kristallographie. Crystalline materials Vol. 218; no. 12; pp. 811 - 818 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
De Gruyter Oldenbourg
01.12.2003
|
Online Access | Get full text |
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Summary: | The crystal structure of CaSiO
-walstromite has been solved and refined by a data set collected
from an inclusion in a diamond single crystal (1135 observed reflections, Mo
, Nonius CAD4,
= 3.46). The crystal structure is almost identical to that of walstromite (Ca
BaSi
). The replacement of Ba
by Ca
causes no significant structural changes (ring silicate; according to F. Liebau:
single rings). The structural differences to wollastonite-II (Ca
Si
) are also relatively small: The Ca positions are almost the same, but the axial Si
-ring is isomorphously replaced by the same ring with the inverse axiality. This constitutes a new principle of isomorphous replacement. Based on density functional theory the equation of state has been predicted. This allows us to estimate the remaining pressure of the investigated CaSiO
inclusion in the diamond to be ≈3 GPa. |
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ISSN: | 2194-4946 2196-7105 |
DOI: | 10.1524/zkri.218.12.811.20547 |