Orbitals dioxygen bonding

INDO calculations on these complexes257 gave a net stabilization of the planar geometry over the tetrahedral one. The nickel-dioxygen bond was formed primarily through the donation and back-donation of electrons using the nu and Jt oxygen orbitals parallel to the molecular plane. 

If we add two electrons to O2 molecule we obtain the peroxide anion, 02 , with the electronic configuration log 2og Itig — note that this time the electrons are added to the Ittg antibonding orbital. The bond order for 02 is /2P - 2 +2 + 4 - 4] = 1. Of the three dioxygen species, 02 has the lowest bond order and the longest bond 149 pm. 

The nature of the metal-to-dioxygen bonding is not well understood.21 Undoubtedly both a and % orbitals of the oxygen atoms play some role. In the most irreversibly formed complexes, i.e. those with the longest O—O bonds, the electronic structure can perhaps be described fairly accurately by postulating a set of three single bonds, two M—O and one O—O. However, this may be too simple a picture, since it has been claimed that electron-spectroscopic results imply the transfer of ca. 1.4 electrons to 02 in... 

Diffusion of dioxygen occurs 102 105 times more slowly with the diffusion coefficient D 10 7 10 10 cm2 s 1 Carbon-centered atom of P changes its orbital hybridization in this reaction and changes the C—C bond angles from 120° to 109°. Since P is macroradical and is surrounded by segments of macromolecules, this process occurs with an activation energy Solubility of dioxygen in the amorphous phase of polymer is about 3 x 10 4-2 x 10 3 mol L 1 atm-1... 

Defined as N = (n - n )/2, where n and n are the numbers of electrons in the bonding and antibonding molecular orbitals, respectively, of the corresponding dioxygen species. e R = alkyl. 

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