Bonding, backbonding, and spin-polarized molecular orbitals:: Basis for magnetism and semiconducting transport in V[TCNE]x∼2

X-ray absorption spectroscopy (XAS) and magnetic circular dichroism (MCD) at the V L-2,L-3 and C and N K edges reveal bonding and backbonding interactions in films of the 400 K magnetic semiconductor V[TCNE](x similar to 2). In V spectra, d(xy)-like orbitals are modeled assuming V2+ in an octahedral ligand field, while d(z)(2) and d(x)(2)-y(2) orbitals involved in strong covalent sigma bonding cannot be modeled by atomic calculations. C and N MCD, and differences in XAS from neutral TCNE molecules, reveal spin-polarized molecular orbitals in V[TCNE](x similar to 2) associated with weaker pi bonding interactions that yield its novel properties.