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Title: Synthesis and structural characterization of Al{sub 4}Si{sub 2}C{sub 5}-homeotypic aluminum silicon oxycarbide, (Al{sub 6-x}Si{sub x})(O{sub y}C{sub 5-y}) (x{approx}0.8 and y{approx}1.6)

We have prepared a new layered oxycarbide, [Al{sub 5.25(5)}Si{sub 0.75(5)}][O{sub 1.60(7)}C{sub 3.40(7)}], by isothermal heating of (Al{sub 4.4}Si{sub 0.6})(O{sub 1.0}C{sub 3.0}) at 2273 K near the carbon-carbon monoxide buffer. The crystal structure was characterized using X-ray powder diffraction, transmission electron microscopy and energy dispersive X-ray spectroscopy (EDX). The title compound is trigonal with space group R3m (centrosymmetric), Z=3, and hexagonal cell dimensions a=0.32464(2) nm, c=4.00527(14) nm and V=0.36556(3) nm{sup 3}. The atom ratios Al:Si were determined by EDX, and the initial structural model was derived by the direct methods. The final structural model showed the positional disordering of one of the three types of Al/Si sites. The reliability indices were R{sub wp}=4.45% (S=1.30), R{sub p}=3.48%, R{sub B}=2.27% and R{sub F}=1.25%. The crystal is composed of three types of domains with nearly the same fraction, one of which has the crystal structure of space group R3-bar m. The crystal structure of the remaining two domains, which are related by pseudo-symmetry inversion, is noncentrosymmetric with space group R3m. - Graphical Abstract: A new aluminum silicon oxycarbide, (Al{sub 6-x}Si{sub x})(O{sub y}C{sub 5-y}) (x{approx}0.8 and y{approx}1.6). The crystal is composed of three types of domains (I, II and III), and hence the structure ismore » represented by a split-atom model. Individual crystal structures can be regarded as layered structures, which consist of A-type [(Al,Si){sub 4}(O,C){sub 4}] unit layers and B-type [(Al,Si)(O,C){sub 2}] single layers.« less
Authors:
; ; ;  [1] ;  [2] ;  [1]
  1. Department of Environmental and Materials Engineering, Nagoya Institute of Technology, Nagoya 466-8555 (Japan)
  2. Cooperative Research Facility Center, Toyohashi University of Technology, Toyohashi 441-8580 (Japan)
Publication Date:
OSTI Identifier:
21483674
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 183; Journal Issue: 9; Other Information: DOI: 10.1016/j.jssc.2010.07.031; PII: S0022-4596(10)00313-0; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ALUMINIUM COMPOUNDS; CARBON; CARBON MONOXIDE; DOMAIN STRUCTURE; HEATING; LATTICE PARAMETERS; LAYERS; ORGANIC OXYGEN COMPOUNDS; SILICON COMPOUNDS; SPACE GROUPS; STRUCTURAL MODELS; SYNTHESIS; TRANSMISSION ELECTRON MICROSCOPY; TRIGONAL LATTICES; X-RAY DIFFRACTION; X-RAY SPECTROSCOPY CARBON COMPOUNDS; CARBON OXIDES; CHALCOGENIDES; COHERENT SCATTERING; CRYSTAL LATTICES; CRYSTAL STRUCTURE; DIFFRACTION; ELECTRON MICROSCOPY; ELEMENTS; MICROSCOPY; NONMETALS; ORGANIC COMPOUNDS; OXIDES; OXYGEN COMPOUNDS; SCATTERING; SPECTROSCOPY; SYMMETRY GROUPS