Crystal structure and Mossbauer spectroscopy of the synthetic amphibole potassic-ferri-ferrorichterite at 298 K and low temperatures (80-110 K)

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doi: 10.1127/0935-1221/2002/0014-0105
Authors:Redhammer, Günther; Roth, Georg
Author Affiliations:Primary:
Rheinisch-Westfälische-Technische Hochschule Aachen, Institute of Crystallography, Aachen, Federal Republic of Germany
Volume Title:European Journal of Mineralogy
Source:European Journal of Mineralogy, 14(1), p.105-114. Publisher: Schweizerbart'sche Verlagsbuchhandlung (Nägele u. Obermiller), Stuttgart, Federal Republic of Germany. ISSN: 0935-1221
Publication Date:2002
Note:In English. 36 refs.; illus., incl. 6 tables
Summary:The crystal structure of synthetic potassic ferri-ferrorichterite, ideally K(Ca0.5Na1.5)Fe5Si8O22(OH)2, with a 10.145, b 18.184, c 5.296 Å, β 104.42°, V 946.3 Å3, Z = 2, space group C2/m, was refined for 298 and 110 K; there is no crystallographic phase transition down to 110 K. The two non-equivalent T sites and the octahedral M1 and M3 sites behave very rigidly on cooling. Bond lengths for the distorted M sites slightly decrease as T is lowered. The tetrahedral chain linking increases by 0.9° between 298 and 110 K. Mössbauer spectra collected at 298 K yield rather high Fe3+ values, up to 2.0 pfu; Fe3+ prefers the M2 site. Three components detected in the ferrous quadrupole splitting distribution of the C-type sites were assigned to the M1, M2 and M3 sites, consistent with polyhedral distortion, and give the correct site occupancies. [R.A.H.]
Sections:Crystal structure
Subsections:Specific structures: silicates
Subjects:Amphibole group; Chain silicates; Crystal structure; High temperature; Mossbauer spectra; Silicates; Spectra; Synthetic materials; Temperature; Ferrorichterite
Abstract Numbers:02M/1359
Record ID:2002024004
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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