Short-range order and twins in ordered titanium monoxide

The structure of annealed titanium monoxide TiO_1.087 containing monoclinic ordered phase Ti₅O₅ was studied by electron diffraction. Along with the set of structural, superstructural, and extra reflections, the diffraction pattern of titanium monoxide shows a set of plane diffuse fringes in the (112) _B1* section of the reciprocal lattice of the basis cubic structure B1. It is shown that some of the extra reflections are due to the twinning of the monoclinic superstructure along the (−1−11) plane of the reciprocal lattice of the basis cubic structure. The diffuse contours enclose plane areas of the reciprocal space with the fixed values of wave vectors K ₁₀₀ ∼ ±(h+0.07)k ₁₀₀, K ₀₁₀ ∼ ±(k+0.07)k ₀₁₀, and K ₀₀₁ ∼± (l+0.07)k ₀₀₁ of the B1 structure. Their appearance is associated with the short-range displacement order.