Planar tetra-, penta-, hexa-, hepta-, and octacoordinate silicons: A universal structural pattern

A universal structural pattern is presented at density functional theory level to incorporate planar tetra-, penta-, hexa-, hepta-, and octacoordinate silicons in C2vBnE2Si series. The structural pattern could be applied to form other planar coordinate nonmetals including Ge, P, As, Al, and Ga, which needs to be confirmed in experiments to open a new branch of chemistry on planar coordinate main group elements.