Synthesis, Characterization and Optical Properties of Two Novel Metal Borates

Two novel metal borates, namely, Ag 7 B 9 O 16 (OH) 2 ( 1 ) and AgCa 2 B 7 O 11 (OH) 4 ( 2 ) were obtained under hydrothermal conditions. Ag 7 B 9 O 16 (OH) 2 crystallizes into the centrosymmetric space group of C2/c in the monoclinic crystal system and displays a unique three‐dimensional (3D) framework built by 1D double borate chains further connected by Ag cations. AgCa 2 B 7 O 11 (OH) 4 also belongs to monoclinic space group C2/c and it features borate chains with B 8 O 8 8‐membered rings along the c axis which are further coordinated via AgO 3 into 2D layers. These layers are bridged via CaO 8 polyhedron into the final 3D framework. Two compounds were further characterized through thermogravimetric and optical analysis and density functional theory calculation have also been carried out, addressing their electronic structures.