Is tin (IV) bromide an ionic or covalent bond?

Question

Is tin (IV) bromide an ionic or covalent bond?

Answer 1

Ionic

For evidence, consult the electronegativities of the two species.

Answer 2

Tin (II) bromide would be ionic, but Tin (IV) bromide would probably have polar bonds (which are midway between pure ionic and pure covalent bonds - think of them as covalent bonds where the electrons spend most time near the bromine atoms).

This is because tin is a poor metal (being in the p-block of the periodic table along with the non-metals).

Answer 3

Ionic???  I don't think so.  Yes, lets take a look at the electronegativities. 2.96 for Br, and 1.96 for Sn.  The DEN is 1.00.  That's well below the 1.67 where the bond is 50% ionic and 50% covalent.  Therefore the Sn-Br bond is polar covalent.  

Next startling fact.  Electronegativities can vary for different oxidation numbers of the same element.  In fact, the higher the oxidation number of the metal the more covalent the bonds.

It melts at 31C which indicates that it does not form an network of positive and negative ions.

The bonds in tin (IV) bromide are covalent bonds.

========= Follow up ==========

Tin (II) bromide bonds are also polar covalent.

Answer 4

Tin has an electronegativity of 1.96. Bromine is 2.96. That's a difference of 1.00. An electronegativity difference of 1.9 or greater is usually associated with a pure ionic bond. You can see that we're not close to that. So SnBr4 has a considerable amount of covalent bonding present. Compare that to CO2 where the C-O electronegativity difference is 0.9, and we usually think of CO2 as covalent.