Effects of structural and chemical characteristics of zeolites on the properties of their bridging hydroxyl groups

Journal Article · Thu Jun 04 04:00:00 EDT 1987 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100296a043· OSTI ID:6371377

Pelmenshchikov, A G; Pavlov, V I; Zhidomirov, G M; Beran, S

The nonempirical SCF method with a STO-3G basis set is used to study the effects of the geometry (SiO and AlO bond lengths and SiOAl angles) and chemical (the Si:Al ratio) characteristics of zeolites on the vibrational frequencies of their OH groups modeled by the H3SiOHAlH3, H3SiOSi(OH)3, and H2AlOSi(OH)3 molecules. It is shown that the values of the vibrational frequencies are particularly affected by the structural characteristics (e.g., changes in the Si-O and Al-O bond lengths and the SiOAl angle of 0.04 x 10 m and 20, respectively, result in shifts of the stretching frequency nu/sub OH/ of up to 40 cm ), while the influence of the chemical composition of zeolites is negligibly small (e.g., a substitution of Al for Si in the third coordination sphere of OH leads to a change of about 1 cm ).

• Research Organization: Institute of Catalysis, Novosibirsk, USSR
• OSTI ID: 6371377
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 91:12; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
ANIONS
BOND ANGLE
BOND LENGTHS
CHALCOGENIDES
CHARGED PARTICLES
CRYSTAL STRUCTURE
DATA
DIMENSIONS
ENERGY LEVELS
EXCITED STATES
HYDROGEN COMPOUNDS
HYDROXIDES
INFORMATION
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
IONS
LENGTH
MATERIALS
MATHEMATICAL MODELS
MINERALS
MOLECULAR MODELS
MOLECULAR STRUCTURE
NUMERICAL DATA
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
SELF-CONSISTENT FIELD
SILICA
SILICON COMPOUNDS
SILICON OXIDES
THEORETICAL DATA
VIBRATIONAL STATES
ZEOLITES