Rb2[B12(OH)12]·2H2O and Rb2[B12(OH)12]·2H2O2: Hydrate and perhydrolate of rubidium dodecahydroxo-closo-dodecaborate

The orthorhombically crystallizing salts Rb2[B12(OH)12]·2H2O (a=1576.81(9), b=813.08(5), c=1245.32(7)pm) and Rb2[B12(OH)12]·2H2O2 (a=1616.54(9), b=814.29(5), c=1260.12(7)pm) could be prepared from Rb2[B12H12] and hydrogen peroxide. Both crystal structures were determined by X-ray single crystal diffraction and refined in the space group Cmce. They are not isostructural to the other compounds containing icosahedral dodecahydroxo-closo-dodecaborate dianions [B12(OH)12]2− and potassium, rubidium or cesium cations already known to literature, but both title compounds crystallize quasi-isotypically exhibiting Rb+ cations in 10-fold oxygen coordination. The hydrogen peroxide adduct (Rb2[B12(OH)12]·2H2O2) is explosive on shock and heat, while the hydrate (Rb2[B12(OH)12]·2H2O) is not.