The chemical compositions of the samples were determined with an X-ray fluorescence (XRF) spectrometer (Bruker,S8 Tiger WDXRF). Prior to the chemical analysis, 1.5 g of samples and 7.5 g of Li2B4O7 were mixed in platinum crucibles, and then these mixtures were melted in a fusion
device at 1300 °C to obtain glass pellets.
The substitution in the unit cell and the position of
iron in the E-3 talc sample was examined by Mössbauer
spectroscopy. For this purpose, the 57Fe Mössbauer
spectrum was obtained at room temperature (300 K)
with a conventional constant acceleration mode using
a 10 mCi 57Co radioactive source (diffused in Rh). A
Normos-90 computer program was used to determine
the Mössbauer parameters. The solid line in the spectrum
represents computer-fitted curves, and dots represent
the experimental points. The velocity scale (±9 mm/s) is
calibrated with metallic iron foil absorber, and isomer shift
(IS) is given with respect to the center (at 0 mm/s) of this
spectrum.
Fourier transform-infrared (FT-IR) spectra of
powdered samples were recorded using the Bruker IFS-
66 series. The infrared spectrum range was 4000–400
cm–1. Samples of 2 mg were thoroughly mixed with 200
mg of spectroscopic grade KBr in an agate mortar. The
mixtures were placed in a hydraulic press and compressed
to produce pellets for recording the spectra. The spectra
of samples were recorded by accumulating 34 scans at 2.0
cm–1 resolution.
Differential thermal and thermogravimetry analyses
(DT/TGA) of the samples were carried out with a
Setaram Setsys Evaluation simultaneous thermal analysis
apparatus. The samples were heated in an Al2
O3
crucible in
the temperature range of 30–1250 °C with a heating rate of
10 °C min–1 in a nitrogen atmosphere. About 25 mg of the
samples was used in each run