  We report here on physical properties and lattice distortion in the new
quasi-one-dimensional spin system TiOBr by x-ray diffraction experiment using
synchrotoron radiation. Comparing the crystal structure between TiOBr and
TiOCl, the difference of b-axis length plays a key role for physical properties
in both systems. By using single crystal of TiOBr, superlattice reflections
were observed at (0 1.5 0) and (0 2.5 0). The temperature dependence of
superlattice reflections imply the first order transition at $T_{c1}$=27K. We
analyzed the data using the simple dimerization model.
