Series of open-framework aluminoborates containing [B5O10] clusters.

Three new open-framework aluminoborates (ABOs), Rb2AlB5O10·4H2O (), [C5N2H16]AlB5O10 (, C5N2H16 = N-ethyl-1,3-diaminopropane) and [H2dap][(CH3)2NH]AlB5O10 (, dap = 1,2-diaminopropane) have been made under solvothermal conditions and characterized by elemental analysis, IR, TGA, UV-vis, powder XRD, single-crystal XRD, fluorescence spectra and NLO determination, respectively. These three ABOs display two structural types: and are isostructural and crystallize in acentric space groups C2221 and P212121 respectively, showing intersecting helical channels and good NLO properties; while, crystallizes in the centrosymmetric space group Pbca and has CrB4 topology, exhibiting intersecting 8-, 11- and 14-ring channels. UV-vis spectral investigation indicates that they are wide-band-gap semiconductors.