How to figure out Coordination number?

Question

What is the coordination number of the complex [Co(en)2F2]+

i have never seen anything with (en) in it and dont know what it stands for aswell, anyone mind helping me out :D?

Please show working out so i know how to do later :D

Thanks

Answer 1

First of all, keep in mind that en (ethylene diammine - H2N-H2C-CH2-NH2) is a bidendate ligand, as one en creates two co-ordination bonds with the central metal atom. Thus two en gives rise to four co ordinate bonds.

Then Fluorine atoms (monodendate ligands) make two bonds with the Central metal atom - Co.

So total number of bonds made by ligands with central metal atom = 4+2 = 6.

Thus the co-ordination number of this complex = 6.

Any more queries??? Still doubtful???