Theoretical analyses of chemical bonding in terminal EThF2 （E=O,S,Se,Te）

Analyses of chemical bonding and geometric structures in species with chalcogen elements EThF（E=O,S,Se,Te） are performed by the density functional theory. Kohn–Sham molecular orbitals and Th–E bond lengths of these species both indicate multiple bond character for the terminal chalcogen complexes. This is also confirmed by natural bond orbital analyses using the oneelectron density matrix generated by relativistic density functional calculations. Theoretical analyses indicate that electron donation from E to Th increases down the chalcogen group（O<S<Se<Te）. These molecules can serve as examples of multiple bonding between actinide elements and selenium or tellurium.