An orthogonal transformation of the oxygen valence AOs belonging to A(1) symmetry to an omega-hybridized sp basis set allows for useful simplifications reducing Huckel transformed matrix for ground state H2O to nearly block- diagonal form. Neglecting delocalization of the hybrid lone pair into the bond, minimization of the resulting Huckel energy shows that for omega not equal 0 the interbond angle opens beyond 90 degrees. A further orthogonal transformation involving the B-2 y AO yields three orthogonal sp(2) hybrids of C-2v symmetry on oxygen which can be engaged in two equivalent straight O-H bonds making the experimental interbond angle and locally minimizing the Huckel energy of the valence electron configuration. (C) 2009 Elsevier B. V. All rights reserved.