The crystal structure of orthoenstatite
Abstract
The crystal structure of a natural orthorhombic enstatite (orthoenstatite) from the Bishopville meteorite, has been refined by the least-squares method using 680 three-dimensional reflections. The space group and the cell dimensions of this orthoenstatite are Pbca and a = 18.210, b = 8.812 and c = 5.178 Å.
The crystal structure of orthoenstatite is compared with that of clinoenstatite and the geometric relationship between the two polymorphs is described. The orthoenstatite structure is shown to be an exact twin of clinoenstatite on a unit-cell scale. The orthorhombic cell is composed of two monoclinic cells of clinoenstatite joined on (100) through a b-glide plane.
The orthoenstatite structure is also compared with the structures of hypersthene and orthoferrosilite. The corresponding interatomic distances show the following characteristics. With increasing Fe replacement of Mg the interatomic distances M–O in the metal octahedra increase. The mean interatomic distances, M–O, of the octahedra can thus be used to determine the Mg:Fe ratio in the octahedral sites. More surprisingly, an increase of Fe in Mg positions is accompanied by a decrease of the mean Si–O distances in the silicate tetrahedra.
Articles in the same Issue
- Zur Absorption der Ewaldwellen; Messungen bei simultaner Reflexion an (111) und ([unk]11) des Germaniums
- Die Verteilung der Valenzelektronen im Mg2Si
- Redetermination of the crystal structure of α-d-glucosamine hydrohalides*
- Crystal structure of d-leucyl glycine hydrobromide*
- The crystal structure of orthoenstatite
- The crystal and molecular structure of l-ornithine hydrochloride
- Untersuchungen über Umweganregung und ihre Vermeidung am Beispiel des Na2BeF4*
- Analysis of density distribution of the outer electrons in hexamine*
- Bestimmung des Elastizitätstensors trikliner Kristalle: Beispiel CuSO4 · 5H2O
- The crystal structure of 2-aminoethyl seleninic acid · HCl, NH2CH2CH2SeOOH · HCl
- Strukturuntersuchung an Bariumazid Ba(N3)2
- Energetics of conducting halides
- The crystal structure of trechmannite, AgAsS2*
- Die Kristallstruktur von Baumhauerit*
- The crystal structure of rubidium hydrogen fumarate, RbC4H3O4
- Die Kristallstruktur von Imidazol, C3N2H4, bei Zimmertemperatur
- Verfeinerung der Kristallstruktur von Benitoit BaTi[Si3O9]
- The crystal structure of In5Bi3
- Über den Ersatz von Li1+ durch Cu1+ in oxidischen Spinellen*
- Cu1+-haltige Doppeloxide mit seltenen Erdmetallen1
- Transformations ordre-désordre de la cordiérite
- The crystal structure and chemical composition of pollucite
- Die optische Orientierung der Plagioklase
- World Directory of Crystallographers
Articles in the same Issue
- Zur Absorption der Ewaldwellen; Messungen bei simultaner Reflexion an (111) und ([unk]11) des Germaniums
- Die Verteilung der Valenzelektronen im Mg2Si
- Redetermination of the crystal structure of α-d-glucosamine hydrohalides*
- Crystal structure of d-leucyl glycine hydrobromide*
- The crystal structure of orthoenstatite
- The crystal and molecular structure of l-ornithine hydrochloride
- Untersuchungen über Umweganregung und ihre Vermeidung am Beispiel des Na2BeF4*
- Analysis of density distribution of the outer electrons in hexamine*
- Bestimmung des Elastizitätstensors trikliner Kristalle: Beispiel CuSO4 · 5H2O
- The crystal structure of 2-aminoethyl seleninic acid · HCl, NH2CH2CH2SeOOH · HCl
- Strukturuntersuchung an Bariumazid Ba(N3)2
- Energetics of conducting halides
- The crystal structure of trechmannite, AgAsS2*
- Die Kristallstruktur von Baumhauerit*
- The crystal structure of rubidium hydrogen fumarate, RbC4H3O4
- Die Kristallstruktur von Imidazol, C3N2H4, bei Zimmertemperatur
- Verfeinerung der Kristallstruktur von Benitoit BaTi[Si3O9]
- The crystal structure of In5Bi3
- Über den Ersatz von Li1+ durch Cu1+ in oxidischen Spinellen*
- Cu1+-haltige Doppeloxide mit seltenen Erdmetallen1
- Transformations ordre-désordre de la cordiérite
- The crystal structure and chemical composition of pollucite
- Die optische Orientierung der Plagioklase
- World Directory of Crystallographers
