Far infrared, X-ray powder diffraction, and chemical investigation of potassium micas

Journal Article · · American Mineralogist; (United States)

OSTI ID:5579343

Schroeder, P A ^[1]

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1. Yale Univ., New Haven, CT (USA)

Study of the IR, XRD, and chemical parameters shows the following relationships: (1) solid solution of OH and F in trioctahedral structures significantly affects torsional vibrational modes, with increasing frequency correlating with increasing F; (2) heating-induced dehydroxylation of dioctahedral species and heating-induced oxidation of Fe{sup 2+} trioctahedral species provide strong evidence that OH-orientation controls the frequency of the interlayer torsional mode; (3) multivariate statistical analysis of potassium-mica intralayer sheet composition and the frequency of the interlayer torsional mode reveals a strong correlation between the vibrational frequency of the K interlayer torsional mode and octahedral sheet composition. The following preliminary formula is presented, assuming 22 O equivalents per unit formula: {nu}{sub i}(cm{sup minus 1}) = 79.6 + 0.96Mg{sup 2+} {minus} 4.23Fe{sup 2+} + 7.61Al{sup 3+} + 9.09Fe{sub 3+} {minus} 4.65Li{sup +} + 2.20F{sup {minus}}. The frequency of the interlayer torsional mode directly reflects the tetrahedral sheet environment. This relationship therefore supports previous suggestions, based on XRD data alone, that the sheet dimensions and distortions of phyllosilicates are controlled largely by the composition of the octahedral layer. (4) Multiple-mode behavior provides evidence for the presence of compositionally different octahedral cation sites within a given structure. However, absorption spectra alone do not provide information about ordering of the octahedral environments.

• OSTI ID: 5579343
• Journal Information: American Mineralogist; (United States), Journal Name: American Mineralogist; (United States) Vol. 75:9-10; ISSN AMMIA; ISSN 0003-004X
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
152002* -- Geothermal Data & Theory-- Properties of Minerals & Rocks
ABSORPTION SPECTROSCOPY
ALKALI METAL COMPOUNDS
CHALCOGENIDES
CHEMICAL PROPERTIES
CHEMICAL REACTIONS
CHEMISTRY
COHERENT SCATTERING
CRYSTAL STRUCTURE
DIFFRACTION
DISPERSIONS
ELECTROMAGNETIC RADIATION
EQUATIONS
FLUORIDES
FLUORINE COMPOUNDS
FREQUENCY DEPENDENCE
GEOCHEMISTRY
HALIDES
HALOGEN COMPOUNDS
HEATING
HYDROXYL RADICALS
INFRARED RADIATION
LATTICE VIBRATIONS
MATERIAL SUBSTITUTION
MATHEMATICS
MICA
MICROSTRUCTURE
MIXTURES
MULTIVARIATE ANALYSIS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
POTASSIUM COMPOUNDS
RADIATIONS
RADICALS
REMOVAL
SCATTERING
SOLID SOLUTIONS
SOLUTIONS
SPECTROSCOPY
STATISTICS
TORSION
X-RAY DIFFRACTION