| Popis: |
The high-pressure ammonium triborate HP-(NH4)B3O5 was synthesized in a high-pressure/high-temperature experiment at 3 GPa and 600 °C. It crystalizes in the monoclinic space group C2/c (No. 15) with the parameters a = 981.0(2), b = 880.2(2), c = 922.2(2) pm, β = 103.8(1)°, V = 0.7735(3) nm3, Z = 8, R1 = 0.0436, and wR2 = 0.1059 (all data). The compound is built up from ribbons of interconnected corner- and edge-sharing BO4 tetrahedra that are linked by planar BO3 groups to form a three-dimensional structure. The ammonium ions are situated in channels, forming four hydrogen bonds to oxygen of the boron oxygen network. The structure is a substitutional variant of the compounds HP-MB3O5, (M = K, Rb) and HP-Cs1–x(H3O)xB3O5 (x = 0.5–0.7). The collected IR and Raman spectra of HP-(NH4)B3O5 show great similarities to the spectra of the analogous phases. |
