Li7SrScB12O24 and Li7Ba0.6Ca0.4ScB12O24: two new quaternary rare-earth borates with short UV cutoff edges

Two new quaternary rare-earth borates, (Li7MScB12O24)-Sc-II (M-II = Sr, Ba0.6Ca0.4), crystallizing in the centrosymmetric space group R3 were synthesized by a high-temperature solution method and characterized. They are isostructural and exhibit a three-dimensional anionic [ScB12O24](9-) framework composed of B6O14 groups and ScO6 octahedra with alkali- and alkaline-earth metal cations occupying the cavities and keeping the charge balance. The UV-Vis-NIR diffuse reflectance spectrum shows that the cutoff edge of Li7SrScB12O24 is less than 200 nm, which indicates its potential application in the deep UV region. (Li7MScB12O24)-Sc-II (M-II = Sr, Ba0.6Ca0.4) will become a new type of rare-earth borates that have a deep-UV cutoff edge (<= 200 nm). Furthermore, infrared spectroscopy and thermal analysis were carried out and the results were analyzed.

Automated summary

Two new quaternary rare-earth borates were synthesized and characterized, showing the potential for applications in the deep UV region.