Tin(II) bromide

Structure and bonding

In the gas phase SnBr2 is non-linear with a bent configuration similar to SnCl2 in the gas phase. The Br-Sn-Br angle is 95° and the Sn-Br bond length is 255pm. There is evidence of dimerisation in the gaseous phase.{{cite journal

Preparation

Tin(II) bromide can be prepared by the reaction of metallic tin and HBr distilling off the H2O/HBr and cooling: :Sn + 2 HBr → SnBr2 + H2

However, the reaction will produce tin (IV) bromide in the presence of oxygen.

Reactions

SnBr2 is soluble in donor solvents such as acetone, pyridine and dimethylsulfoxide to give pyramidal adducts.

A number of hydrates are known, 2SnBr2·H2O, 3SnBr2·H2O and 6SnBr2·5H2O which in the solid phase have tin coordinated by a distorted trigonal prism of 6 bromine atoms with Br or H2O capping 1 or 2 faces. When dissolved in HBr the pyramidal SnBr3− ion is formed. Like SnCl2 it is a reducing agent. With a variety of alkyl bromides oxidative addition can occur to yield the alkyltin tribromide{{cite journal | hdl-access = free :SnBr2 + RBr → RSnBr3

Tin(II) bromide can act as a Lewis acid forming adducts with donor molecules e.g. trimethylamine where it forms NMe3·SnBr2 and 2NMe3·SnBr2 |name-list-style=amp | journal = Inorg. Chem. It can also act as both donor and acceptor in, for example, the complex F3B·SnBr2·NMe3 where it is a donor to boron trifluoride and an acceptor to trimethylamine.{{cite journal |name-list-style=amp | journal = Inorg. Chem.

References

References

1. (2005). "Two Modifications of Tin(II) Bromide". [[Zeitschrift für anorganische und allgemeine Chemie.
2. "Tin(II) bromide".
3. {{Greenwood&Earnshaw
4. J.L Wardell "Tin:Inorganic Chemistry" ''Encyclopedia of Inorganic Chemistry'' Ed: R Bruce King John Wiley & Sons (1994) {{ISBN. 0-471-93620-0
5. "ICSD Entry: 429132". [[Cambridge Crystallographic Data Centre]].
6. "ICSD Entry: 429133". Cambridge Crystallographic Data Centre.
7. {{Cotton&Wilkinson6th