Die Kristallstruktur des Dilithium tetrahydroxo-di-μ-peroxodiborats(Lithiumperoxoborats), Li2[B2(O2)2(OH)4]

Abstract

Abstract The crystal structure of synthetic LiBO2 · H2O2, Li2[B2(O2)2(OH)4], was determined from single-crystal X-ray diffractometer data. The compound is monoclinic, space group P21/c; the lattice constants are a = 704.0(5) pm, b = 788.0(4) pm, c = 508.5(2) pm and β = 97.98(5)°; the unit cell contains Z = 2 formula units Li2[B2(O2)2(OH)4]. The measured density is Dm = 1.97 and the calculated density is Dc = 1.997 Mg · m−2. The crystal structure has been solved from 533 observed reflections by means of the Multan method and refined by least-squares calculations to an index R of 4.5% and Rw of 3.8%. The structure contains the peroxoanion [B2(O2)2(OH)4]2− found already in the structure of triclinic NaBO2 · 3 H2O · H2O2, Na2[B2(O2)2(OH)4] · 6H2O. The Li atom is coordinated by six O atoms with distances between 197.0 and 225.3 pm. Connections between the B – O rings are provided only by the Li+ ions, contrary to the hydrated sodium peroxoborate.