Water‐rich molybdotellurates: Preparation and crystal structure of Li 6 [TeMo 6 O 24 ] · 18 H 2 O and Li 6 [TeMo 6 O 24 ] · Te(OH) 6 · 18 H 2 O

Li 6 [TeMo 6 O 24 ] · 18 H 2 O is triclinic (space group P 1 , a = 1 041.7(1), b = 1 058.6(1), c = 1 070.8(1) pm, α = 61.08(1), β = 60.44(1), γ = 73.95(1)°). Single crystal X‐ray structure analysis (Z = 1, 295 K, 317 parameters, 3 973 reflections, R g = 0.0250) revealed an infinite branched chain of edge‐sharing Li coordination polyhedra to be the prominent structural feature. One of the four crystallographically independent Li + is coordinated octahedrally. The coordination polyhedra of the remaining Li + are distorted trigonal bipyramids. Only three unique oxygen atoms (O(9), O(10), O(12)) of the centrosymmetric [TeMo 6 O 24 ] 6− anion are bound to Li + . The further positions in the coordination spheres of the Li + are occupied by water molecules. Intermolecular hydrogen bonds involve mainly oxygen atoms of the [TeMo 6 O 24 ] 6− anion as nearly equivalent proton acceptors without regard to their different bonding modes to Te and Mo, respectively. Li 6 [TeMo 6 O 24 ] · Te(OH) 6 · 18 H 2 O crystallizes monoclinically in space group P2 1 /n with Z = 4, a = 994.1(3), b = 2 344.8(10), c = 1 764.9(4) pm, and β = 91.36(4)°. Single crystal structure analysis with least squares refinement of 627 parameters (5 900 reflections, 295 K) converged to R g = 0.0324. There are six unique Li + cations. The coordination polyhedra of Li(1), Li(2), Li(3), and Li(4) are linked by common edges to yield an eight membered centrosymmetric strand. The coordination polyhedra of the remaining two Li + sites (Li(5), Li(6)) are connected to a dimeric unit via a common corner. All oxygen atoms of the Te(OH) 6 molecule are involved in the coordination of Li + . However, only three oxygen atoms (O(13), O(18), O(23)) of the [TeMo 6 O 24 ] 6− anion which lacks crystallographic symmetry are involved in the coordination of Li + . The oxygen atoms of the anion act as proton acceptors in hydrogen bonds of predominantly medium strength. Te(OH) 6 molecules and [TeMo 6 O 24 ] 6− anions connected by strong hydrogen bonds form an infinite chain.