Bond symmetry in AX2 type triatomic molecules

Will triatomic molecules of the AX2, AX2E, AX2E2 etc. (e.g. H2O or CO2), where the central molecule is bonded to two identical atoms, always have symmetric bond lengths in the ground state? If so, is there a simple explanation for why this symmetry should result in the lowest possible energy?




When the central atom is bonded to equal atoms, the bonds does not need to be symmetrical. For example
NO2. The order of the bond is 1.5, and the order of the other bond is 2. So they are not the same longer.


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