Publication Date:
2013-10-02
Description:
Far-infrared spectroscopy and X-ray powder diffraction Rietveld structure refinement for the hydrothermal synthetic muscovite series, (a) KAl 3 (Si 3–y Ge y )O 10 (OH,OD) 2 , (b) KGa 3 (Si 3–y Ge y )O 10 (OH,OD) 2 , and (c) K(Al 3–x Ga x )Ge 3 O 10 (OH,OD) 2 , where x = 0.0–3.0, y = 0.0–3.0, and the muscovite–tobelite series, (d) [K 1–A (NH 4 ,ND 4 ) A ]Al 3 Si 3 O 10 (OH,OD) 2 , where A = 0.0–1.0, indicate that there is a complete solid-solution in each series. In the 200–50 cm –1 far-infrared region, four kinds of bands are observed: two bands due to octahedral deformation coupled with OH deformational vibrations between 240 and 130 cm –1 , an in-plane tetrahedral torsional band between 175 and 130 cm –1 , an interlayer I–O inner stretching band, and an I–O outer stretching band. The weak and broad 140 cm –1 band is assigned to K–O inner stretching and the strong broad 110 cm –1 band to K–O outer stretching in muscovite. The broad 175 cm –1 band is (NH 4 /ND 4 )–O inner stretching and the 140 cm –1 broad strong band is (NH 4 /ND 4 )–O outer stretching in tobelite. With increasing Ga-〉Al substitution, the I–O inner and I–O outer stretching bands shift to lower frequency, while with increasing Ge-〉Si substitution, the I–O inner stretching band shifts to higher frequency; the I–O outer stretching bands do not change as a function of composition.
Print ISSN:
0003-004X
Electronic ISSN:
1945-3027
Topics:
Geosciences
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