Topochemical Synthesis of LiCoF3 with a High-Temperature LiNbO3-Type Structure
Topochemical Synthesis of LiCoF3 with a High-Temperature LiNbO3-Type Structure
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高温 LiNbO3 型结构 LiCoF3 的拓扑化学合成
DOI：
10.1021/acs.inorgchem.2c01439
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发表时间：
2022
影响因子：
4.6
通讯作者：
Akamatsu Hirofumi
中科院分区：
文献类型：
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作者：
Matsuo Yumi;Matsukawa Yuko;Kitakado Masahiro;Hasegawa George;Yoshida Suguru;Kubonaka Ryoto;Yoshida Yuya;Kawasaki Tatsushi;Kobayashi Eiichi;Moriyoshi Chikako;Ohno Saneyuki;Fujita Koji;Hayashi Katsuro;Akamatsu Hirofumi
采用有机锂试剂，通过低温锂插层法制得畸变reo3型氟化物cof3，合成了一种耐容因子（0.81）极低的新型钙钛矿氟化物LixCoF3。有趣的是，该反应在室温下15分钟内完成。同步加速器x射线衍射和室温下的光学二次谐波产生表明，该化合物具有Li-Co反位缺陷和a位沿方向分裂的高温linbo3型结构（空间群：R3′c）。a位分裂与基于混合Hartree-Fock密度泛函理论计算的预测一致。Co- l2,3edge x射线吸收光谱以及键价和分析验证了Co离子在锂化相中的二价氧化态，表明其组成接近于LiCoF3（x≈1）。该化合物在36k冷却时呈现顺磁向反铁磁转变，并伴有弱铁磁有序。基于金属氟化物主体低温锂化的合成路线为获得新的linbo3型氟化物家族铺平了道路。
A novel perovskite fluoride, LixCoF3, which has an exceptionally low tolerance factor (0.81), has been synthesized via low-temperature lithium intercalation into a distorted ReO3-type fluoride CoF3using organolithium reagents. Interestingly, this reaction is completed within 15 min at room temperature. Synchrotron X-ray diffractometry and optical second harmonic generation at room temperature have revealed that this compound shows a high-temperature LiNbO3-type structure (space group:R3̅c) involving Li–Co antisite defects andA-site splitting along thecdirection.A-site splitting is consistent with the prediction based on hybrid Hartree–Fock density functional theory calculations. Co-L2,3edge X-ray absorption spectroscopy, as well as bond valence sum analysis, has verified the divalent oxidation state of Co ions in the lithiated phase, suggesting that its composition is close to LiCoF3(x≈ 1). This compound exhibits a paramagnetic-to-antiferromagnetic transition at 36 K on cooling, accompanied by weak ferromagnetic ordering. The synthetic route based on low-temperature lithiation of metal fluorides host paves the way for obtaining a new LiNbO3-type fluoride family.