Nuclear Magnetic Resonance in B2O3sngbnd;H2O Glasses and Boric Acids

摘要

The class of materials B2O3sngbnd;H2O has been investigated over the range B2O3to B2O3middot;3H2O. This includes ``dry'' glassy B2O3, ``wet'' glassy boron oxide of approximate composition B2O3middot;frac12;H2O, monoclinic and orthorhombic forms of metaboric acid, B2O3middot;H2O, and triclinic orthoboric acid, B2O3middot;3H2O. The nuclear quadrupole interaction of the B11isotope was measured and comparisons of the structures are made on the basis of this interaction. It is shown that all substances contain similar planar BO3triangular units. The presence of Osngbnd;Hsngbnd;O hydrogen bonds, as in B2O3middot;3H2O, has a minor effect on the boron nuclear quadrupole interaction. It is concluded that BO4tetrahedral units exist in several of the wet glass samples as well as in monoclinic metaboric acid.