*Communication* **On the Power of Geometry over Tetrel Bonds**

**Ephrath Solel and Sebastian Kozuch \***

Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 841051, Israel; ephrath@post.bgu.ac.il

**\*** Correspondence: kozuch@bgu.ac.il; Tel.: +972-8-64-61192

Received: 29 September 2018; Accepted: 23 October 2018; Published: 24 October 2018

**Abstract:** Tetrel bonds are noncovalent interactions formed by tetrel atoms (as σ-hole carriers) with a Lewis base. Here, we present a computational and molecular orbital study on the effect of the geometry of the substituents around the tetrel atom on the σ-hole and on the binding strengths. We show that changing the angles between substituents can dramatically increase bond strength. In addition, our findings suggest that the established Sn > Ge > Si order of binding strength can be changed in sufficiently distorted molecules due to the enhancement of the charge transfer component, making silicon the strongest tetrel donor.

**Keywords:** tetrel bond; σ-hole; DFT
