  The low-temperature (T = 17.5 K) structure of titanium(III)-oxybromide,
TiOBr, is reported as a two-fold superstructure of the crystal structure at
room temperature. Weak superlattice reflections could be measured with
synchrotron radiation x-rays, and they were analysed by structure refinements
employing superspace techniques. Both the low temperature and room temperature
tructures of TiOBr are isostructural to the corresponding structures of TiOCl.
The results indicate that at low temperatures TiOBr is in a spin-Peierls state
similar to TiOCl, but with the modulations and relevant interactions smaller
than in the latter compound.
