Reinvestigation of crystallographic data and X-ray diffraction data of silicon carbide for polytyje identification purposes

Abstract

Ordinary products of silicon carbide are mixtures of the polytypes, consisting of the ᵦ-phase of the cubic system and many kinds of α-phase of both the hexagonal and rhom-bohedral systems. In addition, their crystallographic and X-ray diffraction data lack consistency among important literatures, such as JCPDS files and Wyckoff's book. These factors have, so far, made the study of silicon carbide difficult. In this paper, many data of the lattice constants collected from the literature are compared and discussed. The α-axis length of hexagonal lattices, which should be constant, was standardized as 3.081 A in consideration of experimental results by the authors and the values in the literature. The c-axis lengths were corrected using the standardized α-value and c/a axis ratios in the literature. Furthermore, interplanar spacings and intensities of diffraction lines were calculated using the standardized and corrected lattice constants and atomic position data. The results were compared with each other and with data of real samples measured by the authors. The present study makes the identification and study of the polytypes easy. © 1993, The Japan Society for Analytical Chemistry. All rights reserved.