Prediction of New Functional Fluorooxoborates with Expected Anionic Framework: A Case of CaB₃O₅F

Abstract The prediction of new fluorooxoborates as ultraviolet (UV)/deep ultraviolet (DUV) opto-electronic functional materials from a largely unexplored chemical space is a challenging task. It has been suggested that the anionic frameworks formed by B–O and B–O–F units significantly determine the physical properties of fluorooxoborates. Therefore, the rational design of anionic frameworks could facilitate the materials discovery process. Herein, we propose that a candidate anionic framework can be efficiently derived from an existing one by slightly altering its oxygen content. Following this idea, we hypothesized the existence of a 1D B₃O₅F_∞ chain from the well-known 2D B₆O₉F_2∞ layer. Accordingly, seven CaB₃O₅F structures with the expected anionic framework were successfully predicted. First-principles calculations show that all these structures have potential in the UV/DUV birefringent or nonlinear optical (NLO) material field, indicating that the 1D B₃O₅F_∞ chain is indeed a promising anionic framework for achieving UV/DUV birefringent and NLO performance.