Structure of α quartz

Abstract

As soon as the structure of β quartz (these Proceedings, A, vol. 109, Sir William Bragg and R. E. Gibbs) was known, it was natural to reconsider that of the α variety and attempt to narrow down the range of uncertainty which existed. The general properties of both varieties of quartz have been dealt with fully in the paper mentioned above, and to avoid repetition it will be necessary to refer to it frequently. In that paper it was shown that the lowering of symmetry from β to α quartz introduced three extra unknown parameters, making four in all, a statement which sums up the whole difficulty of the determination of the α quartz structure. No guiding principle can be introduced simultaneously to aid in its solution, and one is left as before, with intensity measurements alone, to settle not one, but four parameters. However, all the physical properties of quartz suggest that there is but a small change at the transition temperature, and therefore it may be tentatively supposed that no very drastic alteration occurs in the structure.