Titanium falls flat in an eight-membered boron ring


Source: Royal Society of Chemistry

(a) Top and (b) side views of the ball and stick model of the predicted 2D TiB4 monolayer. Titanium and boron atoms are denoted by grey and pink spheres, respectively. The black square marks a unit cell

Researchers in China and the US have predicted the first two-dimensional material to contain completely planar octacoordinate transition metal atoms – TiB4. If scientists can make it, the monolayer would contain edge-sharing wheels of eight-membered boron rings with a central titanium atom.

To uncover the structure, the team combined a swarm-intelligence-based structure search method they had devised in-house with ab initio calculations. They envisage that electron transfer from titanium would compensate for the electron deficient sp2-hybridised boron network. The researchers say this electronic feature, along with the geometric fit of titanium’s atomic radius within the boron ring, would together give the unusual planar structure superior thermodynamic, dynamic and thermal stabilities.