Skip to Main Content
GEOREF RECORD

Twinning in an orthorhombic aluminate sodalite, Ca (sub 8) [Al (sub 12) O (sub 24) ](CrO (sub 4) ) (sub 2)

Ishmael Hassan
Twinning in an orthorhombic aluminate sodalite, Ca (sub 8) [Al (sub 12) O (sub 24) ](CrO (sub 4) ) (sub 2)
Mineralogical Magazine (August 1996) 60 (4): 617-622

Abstract

Transmission electron microscopy (TEM) was used to study the aluminate sodalite, Ca (sub 8) [Al (sub 12) O (sub 24) ](CrO (sub 4) ) (sub 2) . This aluminate sodalite has four polymorphs: one cubic, one modulated, one tetragonal, and an orthorhombic cell that arise from ordering of [Ca (sub 4) .CrO (sub 4) ] (super 6+) clusters that occur in the cages of the structure. The transition temperatures are 432, 453, and 610 K. The cell parameters for the orthorhombic phase, with the cubic cell parameter of a = b = c = 9.222 Aa, are 3a X 2b X c. Transformation twins are formed at 432 K during the transition from the tetragonal to the orthorhombic phase. The twin plane is {110} in the cubic cell, and {320} in the orthorhombic cell.


ISSN: 0026-461X
Serial Title: Mineralogical Magazine
Serial Volume: 60
Serial Issue: 4
Title: Twinning in an orthorhombic aluminate sodalite, Ca (sub 8) [Al (sub 12) O (sub 24) ](CrO (sub 4) ) (sub 2)
Author(s): Hassan, Ishmael
Affiliation: University of Kuwait, Department of Geology, Safat, Kuwait
Pages: 617-622
Published: 199608
Text Language: English
Publisher: Mineralogical Society, London, United Kingdom
References: 20
Accession Number: 1996-073283
Categories: Mineralogy of silicates
Document Type: Serial
Bibliographic Level: Analytic
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, Copyright, Mineralogical Society of Great Britain and Ireland
Update Code: 199622
Close Modal

or Create an Account

Close Modal
Close Modal