Birefringent crystals with significant optical anisotropy have played a pivotal role in laser technology and scientific research by modulating and controlling light polarization. In this study, we have successfully synthesized three new birefringent materials with mixed-valence antimony, namely, KSb₃O₆, RbSb₃O₆, and α-Sb₂O₄, through the introduction of Sb³⁺ with stereochemically active lone pairs (SCALP) to the total oxygen system using a high-temperature solution method. To the best of our knowledge, K/RbSb₃O₆ represents the first alkali metal mixed-valence Sb-based oxide. Interestingly, despite their similar sandwich structure, these materials exhibit vastly different levels of birefringence (almost 10 times difference). It is worth noting that α-Sb₂O₄ demonstrates the largest experimental birefringence (0.201 at 546 nm) among non-π-conjugated Sb-based oxides to date, which can be attributed to the synergistic effect of SCALP group distortion and arrangement. These findings hold valuable implications for guiding future efforts in designing and synthesizing large birefringent materials.

中文翻译：

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立体化学活性孤对电子协同效应诱导的双折射视差


具有显着光学各向异性的双折射晶体通过调制和控制光偏振在激光技术和科学研究中发挥了关键作用。在这项研究中，我们通过使用高温溶液法将具有立体化学活性孤对电子 （SCALP） 的 Sb³⁺ 引入总氧系统，成功地合成了三种具有混合价锑的新型双折射材料，即 KSb₃O₆、RbSb₃O₆ 和 α-Sb₂O₄。据我们所知，K/RbSb₃O₆ 是第一种碱金属混合价 Sb 基氧化物。有趣的是，尽管它们的夹层结构相似，但这些材料表现出截然不同的双折射水平（几乎相差 10 倍）。值得注意的是，α-Sb₂O₄ 在非 π 共轭 Sb 基氧化物中表现出迄今为止最大的实验双折射（在 546 nm 处为 0.201），这可归因于 SCALP 基团畸变和排列的协同效应。这些发现对于指导未来设计和合成大型双折射材料的工作具有有价值的意义。