Search results
Results from the WOW.Com Content Network
The p-orbitals oriented in the z-direction (p z) can overlap end-on forming a bonding (symmetrical) σ orbital and an antibonding σ* molecular orbital. In contrast to the sigma 1s MO's, the σ 2p has some non-bonding electron density at either side of the nuclei and the σ* 2p has some electron density between the nuclei.
Added orbital diagrams for molecular orbitals. 16:49, 21 May 2015: 2,020 × 1,070 (138 KB) Officer781: 2pz MO in wrong orientation relative to the other orbitals per the LCAO notation. 16:40, 21 May 2015: 2,020 × 1,070 (138 KB) Officer781: Moved 2s orbital higher in energy as that MO has more hydrogen admixture.
The qualitative approach of MO analysis uses a molecular orbital diagram to visualize bonding interactions in a molecule. In this type of diagram, the molecular orbitals are represented by horizontal lines; the higher a line the higher the energy of the orbital, and degenerate orbitals are placed on the same level with a space between them.
The orbital diagram breaks down as follows: The 18 framework molecular orbitals, (MOs), derived from the 18 boron atomic orbitals are: 1 bonding MO at the center of the cluster and 5 antibonding MOs from the 6 sp-radial hybrid orbitals; 6 bonding MOs and 6 antibonding MOs from the 12 tangential p-orbitals.
An initial assumption is that the number of molecular orbitals is equal to the number of atomic orbitals included in the linear expansion. In a sense, n atomic orbitals combine to form n molecular orbitals, which can be numbered i = 1 to n and which may not all be the same. The expression (linear expansion) for the i th molecular orbital would be:
The molecular orbital diagram for the final state describes the electronic nature of the molecule in an excited state. Although in MO theory some molecular orbitals may hold electrons that are more localized between specific pairs of molecular atoms, other orbitals may hold electrons that are spread more uniformly over the molecule.
Figure 1: Diagram illustrating σ molecular orbitals of the triiodide anion. The σ molecular orbitals (MOs) of triiodide can be constructed by considering the in-phase and out-of-phase combinations of the central atom's p orbital (collinear with the bond axis) with the p orbitals of the peripheral atoms. [12]
Figure 5: Molecular orbital diagram depiction of frontier orbitals in methane and a basic ML 6 metal complex. As seen above, when a fragment is formed from CH 4, one of the sp 3 hybrid orbitals involved in bonding becomes a nonbonding singly occupied frontier orbital. The frontier orbital’s increased energy level is also shown in the figure.