Inert Pair Effects in Tin and Lead Dihalides: Crystal Structure of Tin(II) Bromide

Halides of the Heavier Group 14 Homologues Germanium, Tin, and Lead—A Journey through Unusual Compounds and Oxidation States

“…SnBr 2 can be prepared in a similar way by heating metallic tin with hydrobromic acid under reflux. The structure of SnBr 2 is related to PbBr 2 , SnCl 2 , and PbCl 2 with the tin atoms having a trigonal‐pyramidal geometry, whereas the pyramid corners share to give polymeric chains of [SnBr 2 ] n . Proceeding from SnCl 2 , a couple of clusters could be isolated in the last decades, mainly through reductive coupling reactions.…”

“…The structure of SnBr 2 is relatedt o PbBr 2 ,S nCl 2 ,a nd PbCl 2 with the tin atoms having at rigonalpyramidal geometry,w hereas the pyramid corners share to give polymericc hains of [SnBr 2 ] n . [47] Proceeding from SnCl 2 ,a couple of clustersc ould be isolated in the last decades, mainly throughr eductive coupling reactions. From 1998t o1 999, Geanangela nd co-workersp ublished the cyclotetrastannanes [{ClSnE(SiMe 3 ) 3 } 4 ]( E = Si, Ge), whicha re obtained by the reaction of SnCl 2 with the organometallic precursors (thf) 3 LiSi(SiMe 3 ) 3 /(thf) 2,5 LiGe(SiMe 3 ) 3 .S tructurally,b oth compounds can be described asS n 4 ring compounds showing a slightly distorted, nearly planar rectangle (fold angle up to 298).…”

Two Modifications of Tin(II) Bromide

“…In Sn II compounds the non‐bonding valence electrons of the tin atoms are generally responsible for stereochemical distortions of the coordination spheres around tin 1. Even in more complex structures the most favorable coordination environment for Sn 2+ is a distorted octahedral coordination to three nearest neighbors and to additional three more distant ligands 2.…”

“…The crystal structure of the corresponding tin(II) chloride dihydrate is affected by the additional coordination of H 2 O forming one‐dimensional chains, 1 ∞ [Sn(H 2 O)ClCl 4/2 ], resulting in a distorted octahedral environment of Sn 2+ 8. In 2010, Abrahams et al reported the crystal structure of alpha‐tin(II) bromide, SnBr 2 , which has been refined by Rietveld analysis of X‐ray powder diffraction data 1. The crystal structure was compared to those of related compounds like PbCl 2 , PbBr 2 and SnCl 2 .…”

“…This can be explained by the non‐bonding valence electrons of Sn, which exhibit a decreasing repulsion along the halide ions. Abrahams et al performed 119 Sn Mössbauer spectroscopy, which revealed a more directional character of these electrons in SnCl 2 and hence a larger repulsive force in SnCl 2 compared to SnBr 2 1…”