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    An alkoxide cluster with 18 Li+ ions encapsulating two borate anions, [(tBuO)12Li18(BO3)2]
    (Blackwell Munksgaard, 2003) Tombul, M.; Errington, R.J.; Coxall, R.A.; Clegg, W.
    The title compound, bis(borato) dodeca(tert-butoxo)octadeca-lithium, [Li-18(BO3)(2)(C4H9O)(12)], is formulated conveniently as [{((BuOLi)-Bu-t)(3)(Li3BO3)}(2)((BuOLi)-Bu-t)(6)]. A central 12-membered ring and two outer six-membered rings are formed by alternating Li+ cations and alkoxide O atoms. Sandwiched between the central ring and each of the outer rings is a planar array of three further Li+ cations surrounding a [BO3](3-) anion. Thus, the molecule consists of a cationic [Li-18((OBu)-Bu-t)(12)](6+) cage encapsulating two borate anions. This compound is the first example of a structurally characterized polynuclear lithium borate, and a rare case of a lithium alkoxide cage with nuclearity greater than eight. All the alkoxide ligands are triply bridging, and the lithium ions have trigonal-planar, trigonal-pyramidal and fourfold coordination, all with major distortions from regular coordination geometry.
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    Poly[μ-aqua-aqua-μ-3-carboxypyrazine-2-carboxylato-sodium(I)]
    (Int Union Crystallography, 2006) Tombul, M.; Güven, K.; Alkış, N.
    The crystal structure of the title compound, [Na(C6H3N2O4)(H2O)(2)](n), consists of molecular ribbons containing octahedral NaO5N units. Two adjacent Na atoms are bridged by two water molecules to give a centrosymmetric dimeric unit. Each Na centre is coordinated by two carboxylate groups. The ligand also uses one N atom to coordinate to Na. In addition, each Na atom is coordinated by one water O atom, raising the coordination number to six. One of the carboxyl groups retains its H atom, which takes part in an O-H center dot center dot center dot O [O center dot center dot center dot O = 2.563 (1) angstrom] intramolecular hydrogen bond.