The Crystal Structures of Two Hydro-closo-Borates with Divalent Tin in Comparison: Sn(H2O)3[B10H10]\u2009·\u20093 H2O and Sn(H2O)3[B12H12]\u2009·\u20094 H2O

Abstract

Single crystals of Sn(H2O)3[B10H10]\u2009·\u20093 H2O and Sn(H2O)3[B12H12]\u2009·\u20094 H2O are easily accessible by reactions of aqueous solutions of the acids (H3O)2[B10H10] and (H3O)2[B12H12] with an excess of tin metal powder after isothermal evaporation of the clear brines. Both compounds crystallize with similar structures in the triclinic system with space group P1¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\bar{1 }$$\\end{document} and Z\u2009=\u20092. The crystallographic main features are electroneutral ∞1{\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${}_{\\infty }^{1} \\{$$\\end{document}Sn(H2O)3/1[B10H10]3/3} and ∞1{\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${}_{\\infty }^{1} \\{$$\\end{document} Sn(H2O)3/1[B12H12]3/3} double chains running along the a-axes. Each Sn2+ cation is coordinated by three water molecules of hydration (d(Sn–O)\u2009=\u2009221–225 pm for the B10 and d(Sn–O)\u2009=\u2009222–227 pm for the B12 compound) and additionally by hydridic hydrogen atoms of the three nearest boron clusters (d(Sn–H)\u2009=\u2009281–322 pm for the B10 and d(Sn–H)\u2009=\u2009278–291 pm for the B12 compound), which complete the coordination sphere. Between these tin(II)-bonded water and the three or four interstitial crystal water molecules, classical bridging hydrogen bonds are found, connecting the double chains to each other. Furthermore, there is also non-classical hydrogen bonding between the anionic [BnHn]2− (n\u2009=\u200910 and 12) clusters and the crystal water molecules pursuant to B–Hδ−⋯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\cdots$$\\end{document}δ+H–O interactions often called dihydrogen bonds.