Acta Crystallographica Section B

Structural Science

Volume 56, Part 5 (October 2000)

research papers

Acta Cryst. (2000). B56, 780-784 [ doi:10.1107/S0108768100003657 ]

Twinning and defects in N-Nb₂O₅

F. E. Rohrer and A.-K. Larsson

Abstract: N-Nb₂O₅ [C2/m (No. 12), a = 28.51, b = 3.830 and c = 17.48 Å, and [beta] = 124.8°] has been investigated by means of selected-area electron diffraction (SAED) and high-resolution transmission electron microscopy (HRTEM). N-Nb₂O₅ is domain twinned, with the twin plane perpendicular to the c* axis. The domains are rather small and the domain twinning can sometimes be best explained as stacking faults. A second type of coherent twinning at an angle of 90° to the other two domain directions was also found. These domains are linked together by areas containing blocks of different sizes, similar to the disordered block arrangement observed in M-Nb₂O₅.