[vvskye]

I know that borane (:BH₃) has a lone pair of electrons and assumes tetrahedral symmetry. How does tetrahydrofuran form a complex with borane when borane is dissolved in it? Since the boron doesn't have any empty orbitals and neither does oxygen, and both are 2nd row elements so I doubt they could accept dative bonds into higher orbitals? Also why would tetrahydrofuran ligate to borane in the first place considering they both have lone pairs, wouldn't they repel each other? I am guessing this has something to do with molecular orbital theory but I could be wrong, any help appreciated

[UG]

I know that borane (:BH₃) has a lone pair of electrons

Hmmm...does it? I think you may need to check this again

[vvskye]

Yes, you're right, I'm being silly using VSEPR without thinking about what's in the valence shell 1s² isn't included evidently. So would I be right in guessing that BH₃ is sp2 hybridized with an empty p orbital? Or would it be sp3 hybridised and that's where the oxygen in the THF ligates to. Either way thanks for the insight

[UG]

So would I be right in guessing that BH₃ is sp2 hybridized with an empty p orbital?

Yes I believe this is the case.