Short belt-like Ca2B2O5·H2O nanostructures: Hydrothermal formation, FT-IR, thermal decomposition, and optical properties

► Hydrothermal synthesis of high crystallinity short belt-like Ca2B2O5·H2O nanostructures (nanobelts). ► Thermal decomposition of Ca2B2O5·H2O nanobelts. ► Thermal conversion route to high crystallinity Ca2B2O5 nanobelts. ► Good transparency of the Ca2B2O5·H2O nanobelts and Ca2B2O5 nanobelts from the ultraviolet to the visible regions.