Valency interaction formula
The Valency Interaction Formula, or VIF provides a way of drawing or interpreting the molecular structural formula based on molecular orbital theory. Valency Points, VP, dots drawn on a page represent valence orbitals. Valency Interactions, VI, that connect the dots, show interactions between these valence orbitals.
Chemical deductions are made from a VIF picture with the application of two pictorial rules. These are linear transformations applied to the quantum operator and preserve invariants crucial to the characterization of the molecules electronic properties, the numbers of bonding, non-bonding, and anti-bonding orbitals and/or the number of doubly, singly, and unoccupied valence orbitals. The two pictorial rules relate all picture with the same electronic properties as characterized by these invariants.
A through presentation of VIF is available through the open access journal symmetry. [1]