BaB2P2O8F2: A Fluoroborophosphate with [B2P2O8F2]∞ Layers and Deep-Ultraviolet Cutoff Edge

A fluoroborophosphate, BaB2P2O8F2, was successfully obtained. Its structure contains a novel [B2P2O8F2]∞ layer containing six-membered rings, which is formed by the fundamental building block composed of three types of non-π-conjugated groups, [PO4], [BO4], and [BO2F2]. BaB2P2O8F2 has a deep-ultraviolet (DUV) cutoff edge (λ < 200 nm) and a tiny birefringence (Δn = 0.007 at 532 nm), which originates from the constituent non-π-conjugated groups. The title compound enriches the versatility of the fluoroborophosphates, encouraging further research into DUV materials in fluoroborophosphate systems.