Pentacoordinated pyramidal structures and bonding properties of WN 10 -/0 : anion photoelectron spectroscopy and theoretical calculations.

Anion photoelectron spectroscopy and theoretical calculations were used to investigate the structural and bonding properties of WN 10 -/0 . The electron affinity of WN 10 is measured to be 1.582 ± 0.030 eV. The frequency of the NN stretch in WN 10 is measured to be 2170 ± 80 cm -1 , which is red-shifted with respect to that of the dinitrogen molecule indicating that the NN bonds are weakened in WN 10 . The theoretical adiabatic detachment energy (ADE) and vertical detachment energy (VDE) of WN 10 - obtained by calculations at the CCSD(T)/CBS level agree well with experimental results. The structures of WN 10 -/0 are C 4v symmetric pentacoordinated pyramidal structures with five end-on dinitrogen ligands. Our experiments show that the peak of WN 10 - is dominant in the mass spectrum of anionic WN n , whereas the mass peak of WN 12 + is dominant in the mass spectrum of cationic WN n , implying that the stabilities of WN n clusters are strongly related to their charge states.