† di-octahedraladj.

Etymology: di- comb. form 1 + octahedral adj.

Crystallography. Obsolete.

Bounded by twice eight planes; i.e. having the form of an octahedral prism with tetrahedral summits.

ΚΠ

1816 R. Jameson Treat. External Characters Minerals (ed. 2) 199 Di-octahedral topaz.

Draft additions 1993

2. Mineralogy. Of a mineral or mineral structure: having two out of every three octahedrally co-ordinated sites in the crystal lattice occupied.

ΘΚΠ

the world > the earth > minerals > types of mineral > silicates > phyllosilicate > [adjective] > dioctahedral series

di-octahedral1946

1946 R. E. Stevens in Bull. U.S. Geol. Surv. No. 950. 103 The formulas of biotite..and of talc...are trioctahedral..whereas those of muscovite..and pyrophyllite..are dioctahedral, having one vacant octahedral position in the formula.

1953 R. E. Grim Clay Mineral. iii. 36 Grim, Bray, and Bradley gave the general formula for illites as (OH)₄K_y(Si_{8 − y}·Al_y) (Al₄·Fe₄·Mg₄·Mg₆)O₂₀. In muscovite y is equal to 2, whereas in illite y is less than 2 and frequently equal to 1 to 1·5. According to the formula, illites would include both trioctahedral and dioctahedral types, and no attempt was made to differentiate between biotite and muscovite types of crystallization. At the present time the name illite is generally used, and will be used herein, for clay-mineral micas of both dioctahedral and trioctahedral types and of muscovite and biotite crystallizations.

1967 Oceanogr. & Marine Biol. 5 155 They did..contain about 10% of dioctahedral montmorillonite together with traces of anhydrite, calcite, and quartz.

1984 N. N. Greenwood & A. Earnshaw Chem. of Elements (1986) ix. 408 The gibbsite series is sometimes called dioctahedral..in obvious reference to the number of octahedral sites occupied in the ‘non-silicate’ layer.

This entry has not yet been fully updated (first published 1896; most recently modified version published online March 2021).

单词	di-octahedral
释义	† di-octahedraladj. Etymology: di- comb. form 1 + octahedral adj. Crystallography. Obsolete. Bounded by twice eight planes; i.e. having the form of an octahedral prism with tetrahedral summits. ΚΠ 1816 R. Jameson Treat. External Characters Minerals (ed. 2) 199 Di-octahedral topaz. Draft additions 1993 2. Mineralogy. Of a mineral or mineral structure: having two out of every three octahedrally co-ordinated sites in the crystal lattice occupied. ΘΚΠ the world > the earth > minerals > types of mineral > silicates > phyllosilicate > [adjective] > dioctahedral series di-octahedral1946 1946 R. E. Stevens in Bull. U.S. Geol. Surv. No. 950. 103 The formulas of biotite..and of talc...are trioctahedral..whereas those of muscovite..and pyrophyllite..are dioctahedral, having one vacant octahedral position in the formula. 1953 R. E. Grim Clay Mineral. iii. 36 Grim, Bray, and Bradley gave the general formula for illites as (OH)₄K_y(Si_{8 − y}·Al_y) (Al₄·Fe₄·Mg₄·Mg₆)O₂₀. In muscovite y is equal to 2, whereas in illite y is less than 2 and frequently equal to 1 to 1·5. According to the formula, illites would include both trioctahedral and dioctahedral types, and no attempt was made to differentiate between biotite and muscovite types of crystallization. At the present time the name illite is generally used, and will be used herein, for clay-mineral micas of both dioctahedral and trioctahedral types and of muscovite and biotite crystallizations. 1967 Oceanogr. & Marine Biol. 5 155 They did..contain about 10% of dioctahedral montmorillonite together with traces of anhydrite, calcite, and quartz. 1984 N. N. Greenwood & A. Earnshaw Chem. of Elements (1986) ix. 408 The gibbsite series is sometimes called dioctahedral..in obvious reference to the number of octahedral sites occupied in the ‘non-silicate’ layer. This entry has not yet been fully updated (first published 1896; most recently modified version published online March 2021). < adj.1816
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