Potential Deep Ultraviolet Phosphate With Y‐Based: 1 [(PO 3 ) 4 ] ∞ Chains AYP 4 O 12 (A = K, NH 4 ) and the First [P 3 O 10 ] Anionic Framework KLiYP 3 O 10

Deep ultraviolet (DUV)optical materials represent a critical frontier in advanced optical material science. In this study, two new Y‐based phosphates, KYP 4 O 12 and NH 4 YP 4 O 12 , were successfully synthesised via high‐temperature solution reactions and conventional solid‐state reactions, featuring one‐dimensional (1D) 1 [(PO 3 ) 4 ] ∞ chain structures. Surprisingly, KLiYP 3 O 10 represents the first Y‐based phosphate exhibiting a zero‐dimensional [P 3 O 10 ] polymer. The experimental cutoff edges of all three compounds are less than 200 nm, and the calculated bandgaps for HSEO6 were all >6.2 eV, demonstrating for the first time the potential of Y‐based phosphates containing 1 [(PO 3 ) 4 ] ∞ chains as optical materials for DUV short wavelengths. First‐principles calculations indicate that the PO framework and [YO 8 ] polyhedron are the primary contributors to the enhanced bandgap. We also conclude that the polymerisation degree of the Y‐based phosphate anion framework is closely correlated with the P/O ratio. This work offers a reference framework and insights for subsequent exploration of DUV materials based on Y‐Based phosphates with one‐dimensional anionic groups.