Liu Shuai, Liu Xiaomeng, Zhao Sangen, Liu Youchao, Li Lina, Ding Qingran, Li Yanqiang, Lin Zheshuai, Luo Junhua, Hong Maochun
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, 350000, P. R. China.
Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.
Angew Chem Int Ed Engl. 2020 Jun 8;59(24):9414-9417. doi: 10.1002/anie.202002828. Epub 2020 Apr 6.
Birefringent materials, which can modulate the polarization of light, are almost exclusively limited to oxides. Peroxides have long been overlooked as birefringent materials, because they are usually not stable in air. Now, the first peroxide birefringent material Rb VO(O ) F is reported, the single crystals of which keep transparency after being exposed in the air for two weeks. Interestingly, Rb VO(O ) F does not feature an optimal anisotropic structure, but its birefringence (Δn=0.189 at 546 nm) exceeds those of the majority of oxides. According to the first-principles calculations, this exceptional birefringence should be attributed to the strong electronic interactions between localized π orbital of O anions and V 3d orbitals, which may be also favorable to the stability in the air for Rb VO(O ) F. These findings distinguish peroxides as a brand-new class of birefringent materials that may possess birefringence superior to the traditional oxides.
能够调制光偏振的双折射材料几乎都局限于氧化物。长期以来，过氧化物一直被忽视作为双折射材料，因为它们在空气中通常不稳定。现在，报道了首个过氧化物双折射材料RbVO(O)F，其单晶在空气中暴露两周后仍保持透明。有趣的是，RbVO(O)F并没有最优的各向异性结构，但其双折射（在546 nm处Δn = 0.189）超过了大多数氧化物。根据第一性原理计算，这种异常的双折射应归因于O阴离子的局域π轨道与V 3d轨道之间强烈的电子相互作用，这也可能有利于RbVO(O)F在空气中的稳定性。这些发现将过氧化物区分为一类全新的双折射材料，其双折射可能优于传统氧化物。
