Planar Nets of Ti Atoms Comprising Squares and Rhombs in the New Binary Antimonide Ti₂Sb

The new binary antimonide Ti2Sb was found to crystallize in a distorted variant of the La2Sb type, which contains a square planar La net with short La−La bonds. In the Ti2Sb structure, the corresponding Ti net is deformed to squares and rhombs in order to enhance Ti−Ti bonding, as proven by single-crystal X-ray investigation in combination with the real-space pair distribution function technique utilizing both X-ray and neutron powder diffraction data. Electronic structure calculations revealed a lowering of the total energy caused by the disorder, the major driving force being strengthened Ti−Ti interactions along the diagonal of the Ti4 rhombs.