Interlayer potassium and its neighboring atoms in micas: Crystal-chemical modeling and XANES spectroscopy
-
Maria Franca Brigatti
,
Daniele Malferrari
Abstract
A detailed description of the interlayer site in trioctahedral true micas is presented based on a statistical appraisal of crystal-chemical, structural, and spectroscopic data determined on two sets of trioctahedral micas extensively studied by both X-ray diffraction refinement on single crystals (SCXRD) and X-ray absorption fine spectroscopy (XAFS) at the potassium K-edge. Spectroscopy was carried out on both random powders and oriented cleavage flakes, the latter setting taking advantage of the polarized character of synchrotron radiation. Such an approach (AXANES) is shown to be complementary to crystal-chemical investigation based on SC-XRD refinement. However, the results are not definitive as they focus on few samples having extreme features only (e.g., end-members, unusual compositions, and samples with extreme and well-identified substitution mechanisms). The experimental absorption K-edge (XANES) for potassium was decomposed by calculation and extrapolated into a full in-plane absorption component (σ||) and a full out-of-plane absorption component (σ⊥). These two patterns reflect different structural features: σ|| represents the arrangement of the atoms located in the mica interlayer space and facing tetrahedral sheets; σ⊥ is associated with multiple-scattering interactions entering deep into the mica structure, thus also reflecting interactions with the heavy atoms (essentially Fe) located in the octahedral sheet. The out-of-plane patterns also provide insights into the electronic properties of the octahedral cations, such as their oxidation states (e.g., Fe2+ and Fe3+) and their ordering (e.g., trans- vs. cis-setting). It is also possible to distinguish between F- and OH-rich micas due to peculiar absorption features originating from the F vs. OH occupancy of the O4 octahedral site. Thus, combining crystal-chemical, structural, and spectroscopic information is shown to be a practical method that allows, on one hand, assignment of the observed spectroscopic features to precise structural pathways followed by the photoelectron within the mica structure and, on the other hand, clarification of the amount of electronic interactions and forces acting onto the individual atoms at the various structural sites.
© 2015 by Walter de Gruyter Berlin/Boston
Articles in the same Issue
- The crystal structure of vurroite, Pb20Sn2(Bi,As)22S54Cl6: OD-character, polytypism, twinning, and modular description
- Mineralogy of the Paso Robles soils on Mars
- Dingdaohengite-(Ce) from the Bayan Obo REE-Nb-Fe Mine, China: Both a true polymorph of perrierite-(Ce) and a titanic analog at the C1 site of chevkinite subgroup
- Thermal equation of state of CaGeO3 perovskite
- Quantitative absorbance spectroscopy with unpolarized light: Part I. Physical and mathematical development
- Quantitative absorbance spectroscopy with unpolarized light: Part II. Experimental evaluation and development of a protocol for quantitative analysis of mineral IR spectra
- Oxide-melt solution calorimetry of selenides: Enthalpy of formation of zinc, cadmium, and lead selenide
- Precise dating of biotite in distal volcanic ash: Isolating subtle alteration using 40Ar/39Ar laser incremental heating and electron microprobe techniques
- Rationale for the existence of four- and eight-reversals in antigorite
- Structural relaxation around substitutional Cr3+ in pyrope garnet
- Metasomatic thorite and uraninite inclusions in xenotime and monazite from granitic pegmatites, Hidra anorthosite massif, southwestern Norway: Mechanics and fluid chemistry
- Interlayer potassium and its neighboring atoms in micas: Crystal-chemical modeling and XANES spectroscopy
- Effect of chemical environment on the hydrogen-related defect chemistry in wadsleyite
- Fracture toughness, hardness, and elastic modulus of kyanite investigated by a depth-sensing indentation technique
- Crystal chemistry of the natrojarosite-jarosite and natrojarosite-hydronium jarosite solid-solution series: A synthetic study with full Fe site occupancy
- A new experimental thin film approach to study mobility and partitioning of elements in grain boundaries: Fe-Mg exchange between olivines mediated by transport through an inert grain boundary
- Titanium as a cathodoluminescence activator in alkali feldspars
- Biogenic vs. abiogenic magnetite nanoparticles: A XMCD study
- Solubility of andradite, Ca3Fe2Si3O12, in a 10 mol% NaCl solution at 800 °C and 10 kbar: Implications for the metasomatic origin of grandite garnet in calc-silicate granulites
- A 3D reconstruction of plagioclase crystals in a synthetic basalt
- Rudashevskyite, the Fe-dominant analogue of sphalerite, a new mineral: Description and crystal structure
- Birchite, a new mineral from Broken Hill, New South Wales, Australia: Description and structure refinement
- Crystal structure of synthetic Al4B2O9: A member of the mullite family closely related to boralsilite
- Interaction of gypsum with As(V)-bearing aqueous solutions: Surface precipitation of guerinite, sainfeldite, and Ca2NaH(AsO4)2·6H2O, a synthetic arsenate
- Jahnsite-(NaFeMg), a new mineral from the Tip Top mine, Custer County, South Dakota: Description and crystal structure
- Evidence for anomalously large degree of polymerization in Mg2SiO4 glass and melt
- Theoretical infrared absorption coefficient of OH groups in minerals
Articles in the same Issue
- The crystal structure of vurroite, Pb20Sn2(Bi,As)22S54Cl6: OD-character, polytypism, twinning, and modular description
- Mineralogy of the Paso Robles soils on Mars
- Dingdaohengite-(Ce) from the Bayan Obo REE-Nb-Fe Mine, China: Both a true polymorph of perrierite-(Ce) and a titanic analog at the C1 site of chevkinite subgroup
- Thermal equation of state of CaGeO3 perovskite
- Quantitative absorbance spectroscopy with unpolarized light: Part I. Physical and mathematical development
- Quantitative absorbance spectroscopy with unpolarized light: Part II. Experimental evaluation and development of a protocol for quantitative analysis of mineral IR spectra
- Oxide-melt solution calorimetry of selenides: Enthalpy of formation of zinc, cadmium, and lead selenide
- Precise dating of biotite in distal volcanic ash: Isolating subtle alteration using 40Ar/39Ar laser incremental heating and electron microprobe techniques
- Rationale for the existence of four- and eight-reversals in antigorite
- Structural relaxation around substitutional Cr3+ in pyrope garnet
- Metasomatic thorite and uraninite inclusions in xenotime and monazite from granitic pegmatites, Hidra anorthosite massif, southwestern Norway: Mechanics and fluid chemistry
- Interlayer potassium and its neighboring atoms in micas: Crystal-chemical modeling and XANES spectroscopy
- Effect of chemical environment on the hydrogen-related defect chemistry in wadsleyite
- Fracture toughness, hardness, and elastic modulus of kyanite investigated by a depth-sensing indentation technique
- Crystal chemistry of the natrojarosite-jarosite and natrojarosite-hydronium jarosite solid-solution series: A synthetic study with full Fe site occupancy
- A new experimental thin film approach to study mobility and partitioning of elements in grain boundaries: Fe-Mg exchange between olivines mediated by transport through an inert grain boundary
- Titanium as a cathodoluminescence activator in alkali feldspars
- Biogenic vs. abiogenic magnetite nanoparticles: A XMCD study
- Solubility of andradite, Ca3Fe2Si3O12, in a 10 mol% NaCl solution at 800 °C and 10 kbar: Implications for the metasomatic origin of grandite garnet in calc-silicate granulites
- A 3D reconstruction of plagioclase crystals in a synthetic basalt
- Rudashevskyite, the Fe-dominant analogue of sphalerite, a new mineral: Description and crystal structure
- Birchite, a new mineral from Broken Hill, New South Wales, Australia: Description and structure refinement
- Crystal structure of synthetic Al4B2O9: A member of the mullite family closely related to boralsilite
- Interaction of gypsum with As(V)-bearing aqueous solutions: Surface precipitation of guerinite, sainfeldite, and Ca2NaH(AsO4)2·6H2O, a synthetic arsenate
- Jahnsite-(NaFeMg), a new mineral from the Tip Top mine, Custer County, South Dakota: Description and crystal structure
- Evidence for anomalously large degree of polymerization in Mg2SiO4 glass and melt
- Theoretical infrared absorption coefficient of OH groups in minerals
