Abstract
A new polyphosphate K2Sr4(PO3)10 is synthesized by a high-temperature solution method. This compound crystallizes in the triclinic space group of P1 ̅, consisting of the 1D infinite [PO3]∞ chains and K and Sr ions between the chains. Compared with AM2(PO3)5 (A = K, Rb, Cs; M = Ba, Pb), K2Sr4(PO3)10 exhibits a more complex [PO3]∞ chain structure and more diverse metal cationic coordination environment. More importantly, K2Sr4(PO3)10 has both a deep-UV cutoff edge (<200 nm) and a significantly enlarged birefringence. First-principles calculations indicate that the birefringence of K2Sr4(PO3)10 is 0.017 at 1064 nm, about 2 times that of RbBa2(PO3)5 (0.008 at 1064 nm), which reaches a new height among the reported mixed alkali metal and alkaline earth metal phosphate. Theoretical calculations and structural analyses show that the enlarged birefringence of K2Sr4(PO3)10 mainly originates from the [PO3]∞ chains arranged in an inverted zigzag. This discovery introduces a new strategy for devising novel phosphate deep-UV optical crystals with a large birefringence.
Original language | English |
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Pages (from-to) | 16215-16221 |
Number of pages | 7 |
Journal | Inorganic Chemistry |
Volume | 62 |
Issue number | 39 |
DOIs | |
Publication status | Published - 2 Oct 2023 |