Iron substitution in soil and synthetic anatase
Iron substitution in soil and synthetic anatase
Clays and Clay Minerals (October 1995) 43 (5): 599-606
- anatase
- chemical properties
- clay mineralogy
- coordination
- crystal chemistry
- EPR spectra
- experimental studies
- infrared spectra
- iron
- metals
- Mossbauer spectra
- oxides
- pseudobrookite
- soils
- spectra
- substitution
- synthesis
- synthetic materials
- TEM data
- thermal effects
- titanium
- unit cell
- X-ray diffraction data
Iron (super III) for Ti (super IV) substitution in the structure of pedogenic and synthetic anatase of up to Fe/(Ti+Fe) 0.1 mol/mol was indicated by an increase in unit cell size as measured by XRD line shifts. Moessbauer- and electron paramagnetic resonance spectra at both, 298 K and 4.2 K supported this by the presence of signals typical for octahedrally coordinated Fe (super III) in a diamagnetic matrix. Charge compensation was achieved by structural OH, as indicated by FTIR bands at 3360 and 960 cm (super -1) , which were absent in pure anatase and which disappeared on heating. The weight loss on heating amounted to ca. 0.5 mol H (sub 2) O/mol Fe. At 600 degrees C structural Fe was ejected, the unit cell size decreased to that of pure anatase, and pseudobrookite, Fe (sub 2) TiO (sub 5) , was formed.
