Anorthite Crystallography

Composition

CaAl2Si2O8

Classification

Plagioclase Feldspar Group Tectosilicate

Structural Parameters

a=8.041, b=12.748, c=13.964 Å
alpha=92.2, beta=115.3, gamma=92.7°
Space Group: P1

atom

x/a

y/b

z/c
Al1 0.0089 0.1685 0.2080
Si1 0.0037 0.8205 0.2374
Si2 0.6916 0.1102 0.3147
Si3 0.6813 0.8819 0.3608
Na1 0.2680 0.9887 0.1465
O1 0.0049 0.1310 0.9666
O2 0.5918 0.9976 0.2804
O3 0.8123 0.1097 0.1901
O4 0.8200 0.8510 0.2587
O5 0.0129 0.3024 0.2706
O6 0.0233 0.6937 0.2291
O7 0.2078 0.1090 0.3890
O8 0.1840 0.8682 0.4362

Reference

Angel, R. J. 1988. High-pressure structure of anorthite. American Mineralogist. 73:1114-1119

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Original release: 1 Oct 1998;