H2O
BO = 2
Problem : experimentally, the σ orbitals are of different energy, as are the nb orbitals.
This problem can not be fixed predictably with the methods we have available
Using more sophisticated MO calculations gives:
B2H6 VBT Lewis Dot structure doesn't have enough electrons:
The B-H-B bonds are called electron deficient bonds (3-center, 2-electron bonds)
MO theory ; break it up into BH3 fragments