Tin(II) bromide 5483579 215741028 2008-05-29T14:29:39Z DOI bot 6652755 Citation maintenance. Initiated by [[User:tarun2k|tarun2k]]. You can [[WP:DOI|use this bot]] yourself! Please [[User:DOI_bot/bugs|report any bugs]]. {{Chembox new | Name = Tin(II) bromide | ImageFile = Tin(II)_bromide.jpg <!-- | ImageSize = 200px --> | ImageName = Tin(II) bromide | OtherNames = tin dibromide, stannous bromide | Section1 = {{Chembox Identifiers | CASNo = 10031-24-0 }} | Section2 = {{Chembox Properties | Formula = SnBr<sub>2</sub> | 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 PbCl<sub>2</sub> }} | Section7 = {{Chembox Hazards | EUClass = not listed }} }} '''Tin(II) bromide''' is a chemical compound of [[tin]] and [[bromine]] with a chemical formula of SnBr<sub>2</sub>. Tin is in the +2 oxidation state. The stability of tin compounds in this oxidation state is attributed to the [[inert pair effect]].<ref name = "Greenwood"> {{Greenwood&Earnshaw}}</ref> <br /> ==Structure and bonding== In the gas phase SnBr<sub>2</sub> is non-linear with a bent configuration similar to SnCl<sub>2</sub> in the gas phase. The Br-Sn-Br angle is 95° and the Sn-Br bond length is 255pm.<ref> J.L Wardell "Tin:Inorganic Chemistry" ''Encyclopedia of Inorganic Chemistry'' Ed: R Bruce King John Wiley & Sons (1994) ISBN 0-4719-3620-0</ref>There is evidence of dimerisation in the gaseous phase.<ref>{{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 }}</ref> The solid state structure is related to that of [[tin(II) chloride|SnCl<sub>2</sub>]] and [[lead(II) chloride|PbCl<sub>2</sub>]] and the tin atoms have five near bromine atom neighbours in an approximately trigonal bipyramidal configuration.<ref>{{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 }}</ref> ==Preparation== Tin(II) bromide can be prepared by the reaction of metallic tin and [[hydrobromic acid|HBr]] distilling off the H<sub>2</sub>O/HBr and cooling<ref name= "Cotton">{{Cotton&Wilkinson6th}}</ref>: :Sn + 2HBr<nowiki>&rarr;</nowiki> SnBr<sub>2</sub> + H<sub>2</sub> ==Reactions== SnBr<sub>2</sub> is soluble in donor solvents such as [[acetone]], [[pyridine]] and [[dimethylsulfoxide]] to give pyramidal adducts<ref name = "Cotton"/><br /> A number of hydrates are known,2SnBr<sub>2</sub>.H<sub>2</sub>O, 3SnBr<sub>2</sub>.H<sub>2</sub>O & 6SnBr<sub>2</sub>.5H<sub>2</sub>O which in the solid phase have tin coordinated by a distorted trigonal prism of 6 bromine atoms with Br or H<sub>2</sub>O capping 1 or 2 faces.<ref name = "Greenwood"> {{Greenwood&Earnshaw}}</ref> When dissolved in [[hydrobromic acid|HBr]] the pyramidal SnBr<sub>3</sub><sup>&minus;</sup> ion is formed.<ref name = "Greenwood" /> Like SnCl<sub>2</sub> it is a reducing agent. With a variety of alkyl bromides oxidative addition can occur to yield the alkyltin tribromide<ref>{{cite journal | title = A convenient synthesis of (C<sub>1</sub>-C<sub>18</sub>) alkyltin tribromides | author = Bulten E.J. | journal = Journal of Oganometallic Chemistv | year = 1975 | volume = 97 | issue = 1 | pages = 167–172 }}</ref> e.g. :SnBr<sub>2</sub> + RBr<nowiki>&rarr;</nowiki> RSnBr<sub>3</sub> Tin(II) bromide can act as a [[Lewis acid]] forming adducts with donor molecules e.g. [[trimethylamine]] where it forms NMe<sub>3</sub>.SnBr<sub>2</sub> and 2NMe<sub>3</sub>.SnBr<sub>2</sub> <ref>{{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 }}</ref> It can also act as both donor and acceptor in, for example, the complex F<sub>3</sub>B.SnBr<sub>2</sub>.NMe<sub>3</sub> where it is a donor to [[boron trifluoride]] and an acceptor to [[trimethylamine]]. <ref>{{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 }}</ref> ==References== {{reflist}} [[Category:Bromides]] [[Category:Tin compounds]] [[ar:بروميد قصدير ثنائي]]