Abstract
Recent advances in high-pressure experimental techniques have yielded high-quality x-ray diffraction data for the high-pressure phases of the group-15 elements Bi, Sb and As, and have made it possible to solve several long-standing problems in their structures. In particular, several complex incommensurate host–guest structures have been identified. This paper reviews the present state of knowledge of the structural transition sequences for these elements at high pressure and room temperature, including a summary of previous work, a detailed presentation of the new structures, and revised equations of state.
Acknowledgements
We thank Dr. V. Degtyareva for first drawing our attention to the similarities between the published structures of Bi-III and Ba-IV, and for stimulating discussions, and our colleagues Dr. S. A. Belmonte, Dr. D. Allan and Dr. S. Rekhi for assistance with the experimental work. We gratefully acknowledge the contributions of our collaborators Prof S. van Smaalen and Dr. L. Palatinus to the solution of the modulated structures of Bi-III and Sb-II. We would like to thank Dr. M. Roberts and Dr. S. Teat of Daresbury Laboratory for assistance in setting up beamlines 9.1 and 9.8, respectively, and Dr. M. Hanfland of the ESRF for setting up beamline ID09. This work was supported by grants from EPSRC and the Royal Society, funding from CCLRC, and facilities provided by Daresbury Laboratory. O.D acknowledges an EPSRC studentship and a UK scholarship for International Research Students.