Structures and bonding of C2X2Y q (X=Si,Ge,Sn,Pb; Y=C,Si,Ge,Sn,Pb; q = +1,0,−1): π-type templates for planar tetracoordinate heavier group 14 atoms

Contrasting the big family of the planar tetracoordinate carbon (ptC), species featuring the planar tetracoordinate heavier group element M (ptM) have been largely limited. Effective structural fra...