A New Tubular Borate Built By [B14O24(OH)6]12− Cluster Units

A new mixed alkali and alkaline-earth metal borate Na4Ca2[B14O22(OH)6]·2H2O(1) has been made under a mild solvothermal condition and characterized by single-crystal X-ray diffraction, infrared(IR) spectroscopy, UV-Vis diffuse reflectance spectroscopy, powder X-ray diffraction and thermogravimetric analysis, respectively. Compound 1 features a 1D tube based on [B14O24(OH)6]12−({B14}-1) oxo-boron clusters. Such a tube built by {B14}-1 units has been discovered for the first time in borate system. These tubes are arranged orderly to generate 2D layers and a further 3D supramolecular network through hydrogen bond interactions. UV-Vis diffuse reflectance spectrum reveals that compound 1 is a wide band-gap semiconductor and has potential application in UV region.