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Can someone please explain how these compounds are formed/how the 3c 2e comes into existence.

  1. Polymeric structure of BeCl2 - 3c 4e
  2. BeH2 - 3c 2e
  3. CH5+

Please explain in terms of the hybridization of the central atom and how the electrons are shared etc. Thanks!

My approach -

I know that in B2H6 there is a banana bond (3c 2e), but in BH3 it makes more sense - both B go into sp3 hybridization, and one hybrid orbital of each is empty where some overlapping takes place due to the H bonded with the other B, thus causing the electron pair to jump from one B to another. Thus named banana bond. With CH5 I don't understand how C is able to hybridize in a way such that it can have a banana bond. I read that it is of the form CH3 and H2 and 3c 2e bonding in between them, but I don't understand how it takes place. For BeCl2 there are 2 Be having 2 Cls each and also coordinate bond by other 2 chlorines. Is that right? But for BeH2, how can there be a 3c 2e bond? I mean based on the same principle, there must be a bond between Be, H that can jump to the other Be with same H, but Be doesn't have enough electrons to do this. Thus my confusion.

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