High-pressure crystal structure of the non-linear optical compound BiB3O6 from two-dimensional powder diffraction data
A method recently proposed by the authors for automatic detection, calibration and evaluation of Debye-Scherrer ellipses using pattern-recognition techniques and advanced signal filtering was applied to the 2D powder diffraction data of the non-ferroelectric, non-centrosymmetric non-linear optical compound α-BiB
3O
6 as a function of pressure. A non-linear compression behaviour over the entire pressure range is observed. At a pressure above 6.1 GPa, a first-order phase transition is observed, which is mainly characterized by a reorientation of the [BO
3]
3- triangles, the [BO
4]
5- tetrahedra and the lone electron pair which is localized at Bi
3+ , in order to optimize crystal packing (see figure).
R.E. Dinnebier, B. Hinrichsen, A. Lennie and M. Jansen