- Tin(II) bromide
Chembox new
Name = Tin(II) bromide
ImageFile = Tin(II)_bromide.jpg
ImageName = Tin(II) bromide
OtherNames = tin dibromide, stannous bromide
Section1 = Chembox Identifiers
CASNo = 10031-24-0
Section2 = Chembox Properties
Formula = SnBr2
MolarMass = 278.518 g/mol
Appearance = yellow powder
Density = 5.12 g/cm³, solid
Solubility = ?
MeltingPt = 215°C
BoilingPt = 639°C
Section3 = Chembox Structure
CrystalStruct = related to PbCl2
Section7 = Chembox Hazards
EUClass = not listedTin(II) bromide is a chemical compound of
tin andbromine with a chemical formula of SnBr2. Tin is in the +2 oxidation state. The stability of tin compounds in this oxidation state is attributed to theinert pair effect . Greenwood&Earnshaw]tructure 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. [ J.L Wardell "Tin:Inorganic Chemistry" "Encyclopedia of Inorganic Chemistry" Ed: R Bruce King John Wiley & Sons (1994) ISBN 0-4719-3620-0] There is evidence of dimerisation in the gaseous phase. [cite journal
title = Thermochemistry of tetrabromoditin and bromoiodotin gaseous
author = K. Hilpert, M. Miller, F. Ramondo
journal =J. Phys. Chem.
year = 1991
volume = 95
issue = 19
pages = 7261–7266
doi = 10.1021/j100172a031] The solid state structure is related to that of SnCl2 and PbCl2 and the tin atoms have five near bromine atom neighbours in an approximately trigonal bipyramidal configuration. [cite journal
title = Inert Pair Effects in Tin and Lead Dihalides: Crystal Structure of Tin(II) Bromide
author = Abrahams I.; Demetriou D.Z.
journal =Journal of Solid State Chemistry
year = 2000
volume = 149
issue = 1
pages = 28–32
doi = 10.1006/jssc.1999.8489]Preparation
Tin(II) bromide can be prepared by the reaction of metallic tin and HBr distilling off the H2O/HBr and coolingCotton&Wilkinson6th] ::Sn + 2HBr
→ SnBr2 + H2Reactions
SnBr2 is soluble in donor solvents such as
acetone ,pyridine anddimethylsulfoxide to give pyramidal adducts
A number of hydrates are known,2SnBr2.H2O, 3SnBr2.H2O & 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. Greenwood&Earnshaw] 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
title = A convenient synthesis of (C1-C18) alkyltin tribromides
author = Bulten E.J.
journal = Journal of Oganometallic Chemistv
year = 1975
volume = 97
issue = 1
pages = 167–172] e.g.:SnBr2 + RBr→ RSnBr3Tin(II) bromide can act as a
Lewis acid forming adducts with donor molecules e.g.trimethylamine where it forms NMe3.SnBr2 and 2NMe3.SnBr2 [cite journal
title = Synthesis and studies of trimethylamine adducts with tin(II) halides
author = Chung Chun Hsu and R. A. Geanangel
journal = Inorg. Chem.
year = 1977
volume = 16
issue = 1
pages = 2529–2534
doi = 10.1021/ic50176a022] It can also act as both donor and acceptor in, for example, the complex F3B.SnBr2.NMe3 where it is a donor toboron trifluoride and an acceptor totrimethylamine . [cite journal
title = Donor and acceptor behavior of divalent tin compounds
author = Chung Chun Hsu and R. A. Geanangel
journal = Inorg. Chem.
year = 1980
volume = 19
issue = 1
pages = 110–119
doi = 10.1021/ic50203a024]References
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