Li2Sr4B12O23: A new alkali and alkaline-earth metal mixed borate with [B10O18]6− network and isolated [B2O5]4− unit

A novel ternary lithium strontium borate Li2Sr4B12O23 crystal with size up to 20 mm×10 mm×4 mm has been grown via the top-seeded solution growth method below 730 °C. Single-crystal XRD analyses showed that Li2Sr4B12O23 crystallizes in the monoclinic space group P21/c with a=6.4664(4) Å, b=8.4878(4) Å, c=15.3337(8) Å, β=102.02(3)°, Z=2. The crystal structure is composed of [B10O18]6− network and isolated [B2O5]4− unit. The IR spectrum further confirmed the presence of both BO3 and BO4 groups. TG-DSC and Transmission spectrum were reported. Band structures and density of states were calculated. - Graphical abstract: A new phase, Li2Sr4B12O23, has been discovered in the ternary M2O–M′O–B2O3 (M=alkali-metal, M′=alkalineearth metal) system. The crystal structure consists of [B10O18]6− network and isolated [B2O5]4− unit. Highlights: ► Li2Sr4B12O23 is a a novel borate discovered in the M2O–M′O–B2O3 (M=alkali-metal, M′=alkaline-earth metal) system. ► Li2Sr4B12O23 crystal structure has a three-dimensional crystal structure with [B10O18]6− network and isolated [B2O5]4− unit. ► Sr1 and Sr2 are located in two different channels constructed by 3∞[B10O18] network.