High-pressure crystal structure of the non-linear optical compound BiB₃O₆ from two-dimensional powder diffraction data

Acta Cryst. (2009). B65, 1-10 [doi.org/10.1107/S0108768108029340]

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-BiB₃O₆ 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 [BO₃]^3- triangles, the [BO₄]^5- tetrahedra and the lone electron pair which is localized at Bi³⁺ , in order to optimize crystal packing (see figure).

R.E. Dinnebier, B. Hinrichsen, A. Lennie and M. Jansen