The lanthanum dodecahydro-closo-dodecaborate hydrate [La(H2O)(9)](2)[B12H12](3) center dot 15 H2O and its oxonium-chloride derivative [La(H2O)(9)](H3O)Cl-2[B12H12] center dot H2O

By neutralization of an aqueous solution of the free acid (H3O)(2)[B12H12] with basic La2O3 and after isothermic evaporation colourless, face-rich single crystals of a water-rich lanthanum(111) dodecahydro-closo-dodecaborate hydrate [La(H2O)(9)](2)[B12H12](3) center dot 15 H2O are isolated. The compound crystallizes in the trigonal system with the centrosymmetric space group R (3) over barc (a = 1189.95(2), c = 7313.27(9) pm, c/a = 6.146; Z = 6; measuring temperature: 100 K). The crystal structure of [La(H2O)(9)](2)[B12H12](3) center dot 15 H2O can be characterized by two of each other independent, one into another posed motives of lattice components. The [B12H12](2-) anions (d(B-B) = 177-179 pm; d(B-H) = 105-116 pm) are arranged according to the samarium structure, while the La 31 cations are arranged according to the copper structure. The lanthanum cations are coordinated in first sphere by nine oxygen atoms from water molecules in form of a threecapped trigonal prism (d(La-O) = 251-262 pm). A coordinative influence of the [B12H12](2-) anions on La3+ has not been determined. Since zeolitic water of hydratation is also present, obviously the classical H-O delta-center dot center dot center dot H+delta-O-hydrogen bonds play a significant role in the stabilization of the crystal structure. During the conversion of an aqueous solution of (H3O)(2)[B12H12] with lanthanum trichloride an anion-mixed salt with the composition [La(H2O)(9)](H3O)Cl-2[B12H12] center dot H2O is obtained. The compound crystallizes in the hexagonal system with the non-centrosymmetric space group P (6) over bar c2 (a = 808.84(3), c = 2064.51(8) pm, c/a = 2.552; Z = 2; measuring temperature: 293 K). The crystal structure can be characterized as a layer-like structure, in which [B12H12](2-) anions and H3O+ cations alternate with layers of [La(H2O)(9)](3+) cations (d(La-O) = 252-260 pm) and Cl- anions along [001]. The [B12H12](2-) (d(B-B) = 176-179 pm; d(B-H) = 104-113 pm) and Cl- anions exhibit no coordinative influence on La3+. Hydrogen bonds are formed between the H3O+ cations and [B12H12](2-) anions, also between the water molecules of [La(H2O)(9)](3+) and Cl- anions, which contribute to the stabilization of the crystal structure.