H sub 6 Si sub 2 O sub 7 : Ab initio molecular orbital calculations show two geometric conformations

Journal Article · Fri Nov 01 04:00:00 EST 1991 · Geochimica et Cosmochimica Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(91)90506-Z· OSTI ID:5211737

Burkhard, D J.M.; De Jong, B H.W.S.; Meyer, A J.H.M.; Van Lenthe, J H ^[1]

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1. Univ. of Utrecht (Netherlands)

The canonical H{sub 6}Si{sub 2}O{sub 7} molecule has been used over the last twenty years to characterize by molecular orbital calculations properties of the Si-O bond in silica containing aqueous solutions, crystalline, or amorphous silicates. The fact that constrained calculations reproduced all essential properties within the accuracy of experimental observations inspired the authors to optimize without any constraints the energy and geometry of such molecule by means of ab initio molecular orbital calculations, and to match the calculated properties of the true geometry of H{sub 6}Si{sub 2}O{sub 7} with properties for silica materials. Their ab initio calculations reveal the following features: a local total energy minimum at < Si-O-Si of 135{degrees} and a slightly lower minimum at 123{degrees}, associated with one and two hydrogen-oxygen bridges.

• OSTI ID: 5211737
• Journal Information: Geochimica et Cosmochimica Acta; (United States), Journal Name: Geochimica et Cosmochimica Acta; (United States) Vol. 55:11; ISSN GCACA; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
BINDING ENERGY
BOND LENGTHS
CHALCOGENIDES
CHEMICAL BONDS
CHEMISTRY
DIMENSIONS
ENERGY
GEOCHEMISTRY
GEOMETRY
LENGTH
MATHEMATICS
MOLECULAR STRUCTURE
OXIDES
OXYGEN COMPOUNDS
SILICON COMPOUNDS
SILICON OXIDES
STRUCTURAL CHEMICAL ANALYSIS