Tin(II) bromide

Tin(II) bromide
Other names
tin dibromide, stannous bromide
10031-24-0 YesY
3D model (Jmol) Interactive image
ChemSpider 59609 N
ECHA InfoCard 100.030.067
EC Number 233-087-0
PubChem 66224
UNII 55F23H2K96 N
Molar mass 278.518 g/mol
Appearance yellow powder
Density 5.12 g/cm3, solid
Melting point 215 °C (419 °F; 488 K)
Boiling point 639 °C (1,182 °F; 912 K)
related to PbCl2
not listed
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Tin(II) bromide is a chemical compound of tin and bromine 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 the inert pair effect.[1]

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.[2] There is evidence of dimerisation in the gaseous phase.[3] 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.[4]


Tin(II) bromide can be prepared by the reaction of metallic tin and HBr distilling off the H2O/HBr and cooling:[5]

Sn + 2HBr SnBr2 + H2


SnBr2 is soluble in donor solvents such as acetone, pyridine and dimethylsulfoxide to give pyramidal adducts.[5]
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.[1] When dissolved in HBr the pyramidal SnBr3 ion is formed.[1] Like SnCl2 it is a reducing agent. With a variety of alkyl bromides oxidative addition can occur to yield the alkyltin tribromide[6] e.g.

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 [7] 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. [8]


  1. 1 2 3 Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 0-08-037941-9.
  2. J.L Wardell "Tin:Inorganic Chemistry" Encyclopedia of Inorganic Chemistry Ed: R Bruce King John Wiley & Sons (1994) ISBN 0-471-93620-0
  3. K. Hilpert; M. Miller; F. Ramondo (1991). "Thermochemistry of tetrabromoditin and bromoiodotin gaseous". J. Phys. Chem. 95 (19): 7261–7266. doi:10.1021/j100172a031.
  4. Abrahams I.; Demetriou D.Z. (2000). "Inert Pair Effects in Tin and Lead Dihalides: Crystal Structure of Tin(II) Bromide". Journal of Solid State Chemistry. 149 (1): 28–32. Bibcode:2000JSSCh.149...28A. doi:10.1006/jssc.1999.8489.
  5. 1 2 Cotton, F. Albert; Wilkinson, Geoffrey; Murillo, Carlos A.; Bochmann, Manfred (1999), Advanced Inorganic Chemistry (6th ed.), New York: Wiley-Interscience, ISBN 0-471-19957-5
  6. Bulten E.J. (1975). "A convenient synthesis of (C1-C18) alkyltin tribromides". Journal of Oganometallic Chemistv. 97 (1): 167–172. doi:10.1016/S0022-328X(00)89463-2.
  7. Chung Chun Hsu & R. A. Geanangel (1977). "Synthesis and studies of trimethylamine adducts with tin(II) halides". Inorg. Chem. 16 (1): 2529–2534. doi:10.1021/ic50176a022.
  8. Chung Chun Hsu & R. A. Geanangel (1980). "Donor and acceptor behavior of divalent tin compounds". Inorg. Chem. 19 (1): 110–119. doi:10.1021/ic50203a024.
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