Synthesis and structural characterization of Al{sub 4}SiC{sub 4}-homeotypic aluminum silicon oxycarbide, [Al{sub 4.4}Si{sub 0.6}][O{sub 1.0}C{sub 2.0}]C

Journal Article · Mon Mar 15 00:00:00 EDT 2010 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2010.01.012· OSTI ID:21372532

Kaga, Motoaki; Iwata, Tomoyuki ^[1]; Nakano, Hiromi ^[2]; Fukuda, Koichiro ^[1]

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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)

A new quaternary layered oxycarbide, [Al{sub 4.39(5)}Si{sub 0.61(5)}]{sub S}IGMA{sub 5}[O{sub 1.00(2)}C{sub 2.00(2)}]{sub S}IGMA{sub 3}C, has been synthesized and characterized by X-ray powder diffraction, transmission electron microscopy and energy dispersive X-ray spectroscopy (EDX). The title compound was found to be hexagonal with space group P6{sub 3}/mmc, Z=2, and unit-cell dimensions a=0.32783(1) nm, c=2.16674(7) nm and V=0.20167(1) 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 maximum-entropy methods-based pattern fitting (MPF) method was used to confirm the validity of the split-atom model, in which conventional structure bias caused by assuming intensity partitioning was minimized. The reliability indices calculated from the MPF were R{sub wp}=3.73% (S=1.20), R{sub p}=2.94%, R{sub B}=1.04% and R{sub F}=0.81%. The crystal was an inversion twin. Each twin-related individual was isostructural with Al{sub 4}SiC{sub 4} (space group P6{sub 3}mc, Z=2). - Graphical abstract: A new oxycarbide discovered in the Al-Si-O-C system, Al{sub 4}SiC{sub 4}-homeotypic [Al{sub 4.4}Si{sub 0.6}][O{sub 1.0}C{sub 2.0}]C. The crystal is an inversion twin, and hence the structure is represented by a split-atom model. The three-dimensional electron density distributions are determined by the maximum-entropy methods-based pattern fitting, being consistent with the disordered structural model.

• OSTI ID: 21372532
• Journal Information: Journal of Solid State Chemistry, Vol. 183, Issue 3; Other Information: DOI: 10.1016/j.jssc.2010.01.012; PII: S0022-4596(10)00013-7; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALUMINIUM COMPOUNDS
CALCULATION METHODS
ELECTRON DENSITY
ENTROPY
HCP LATTICES
LATTICE PARAMETERS
OXYCARBIDES
SILICON COMPOUNDS
SPACE GROUPS
STRUCTURAL MODELS
SYNTHESIS
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION
X-RAY SPECTROSCOPY
CARBON COMPOUNDS
COHERENT SCATTERING
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DIFFRACTION
ELECTRON MICROSCOPY
HEXAGONAL LATTICES
MICROSCOPY
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SCATTERING
SPECTROSCOPY
SYMMETRY GROUPS
THERMODYNAMIC PROPERTIES