title: Dilithium hexa-hydroxidostannate(IV) dihydrate, a second monoclinic modification with a layer structure.
abstract: The title compound, Li2[Sn(OH)6]·2H2O, is dimorphic. As for the previously described α-modification, the title β-modification crystallizes in the monoclinic system and contains the same primary building units, viz [Sn(OH)6](2-) octa-hedra and [Li(μ2-OH)3(H2O)] tetra-hedra. In contrast to the Sn-O bond lengths that are very similar in both modifications, the Li-O bond lengths differ significantly, in particular those involving the water mol-ecule. In the new β-modification, the primary building units are linked into layers parallel to (010). The [Sn(OH)6](2-) octa-hedra (-1 symmetry) form hexa-gonal nets and the [Li(μ2-OH)3(H2O)] tetra-hedra are situated in between, with their apices in an alternating fashion up and down. O-H⋯O hydrogen bonds between OH groups and water mol-ecules exist within the layers as well as between them.
authors.affiliation: Institut für Chemie neuer Materialien, Strukturchemie, Universität Osnabrück, Barbarastrasse 7, D-49069 Osnabrück, Germany.
authors.forename: Shouassi
authors.initials: S
authors.lastname: Kamaha
authors.forename: Hans
authors.initials: H
authors.lastname: Reuter