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Precision lattice parameters and the coefficients of thermal expansion of hexagonal germanium dioxide
Author(s) -
Rao K. V. K.,
Naidu S. V. N.,
Iyengar L.
Publication year - 1973
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889873008307
Subject(s) - tetragonal crystal system , thermal expansion , germanium , hexagonal crystal system , materials science , atmospheric temperature range , lattice (music) , perpendicular , rutile , quartz , thermal , condensed matter physics , crystallography , thermodynamics , crystal structure , chemistry , geometry , composite material , mathematics , physics , metallurgy , silicon , acoustics , organic chemistry
With a Unicam 19 cm high‐temperature powder camera, precision lattice parameters of hexagonal germanium dioxide have been determined at various temperatures in the range 36 to 516 °C by the X‐ray method. From these data the coefficients of thermal expansion have been evaluated by a graphical method. The temperature dependence of the coefficients of thermal expansion, α || and α ⊥ , parallel and perpendicular to the principal axis respectively, are represented by the following equations:where T is the numerical value of the temperature expressed in °C. The thermal expansion of hexagonal GeO 2 has been compared with that of the isomorphous α‐quartz and the polymorphous tetragonal rutile‐type GeO 2 .