Delville M H, Barbut D, Wattiaux A, Bassat J M, Ménétrier M, Labrugère C, Grenier J C, Etourneau J
CNRS, Université de Bordeaux, ICMCB, 87 avenue du Dr. A. Schweitzer, Pessac, F-33608, France.
Inorg Chem. 2009 Aug 17;48(16):7962-9. doi: 10.1021/ic900912d.
The fluorination of La(2)CuO(4) was achieved for the first time under normal conditions of pressure and temperature (1 MPa and 298 K) via electrochemical insertion in organic fluorinated electrolytes and led to lanthanum oxyfluorides of general formula La(2)CuO(4)F(x). Analyses showed that, underneath a very thin layer of LaF(3) (a few atomic layers), fluorine is effectively inserted in the material's structure. The fluorination strongly modifies the lanthanum environment, whereas very little modification is observed on copper, suggesting an insertion in the La(2)O(2) blocks of the structure. In all cases, fluorine insertion breaks the translation symmetry and introduces a long-distance disorder, as shown by electron spin resonance. These results highlight the efficiency of electrochemistry as a new "chimie douce" type fluorination technique for solid-state materials. Performed at room temperature, it additionally does not require any specific experimental care. The choice of the electrolytic medium is crucial with regard to the fluorine insertion rate as well as the material deterioration. Successful application of this technique to the well-known La(2)CuO(4) material provides a basis for further syntheses from other oxides.
通过在有机氟化物电解质中进行电化学嵌入，首次在常压和常温条件下（1兆帕和298开尔文）实现了La₂CuO₄的氟化，得到了通式为La₂CuO₄Fₓ的氟氧化镧。分析表明，在极薄的LaF₃层（几个原子层）之下，氟有效地嵌入了材料结构中。氟化强烈改变了镧的环境，而铜的变化很小，这表明氟嵌入了结构的La₂O₂块中。在所有情况下，如电子自旋共振所示，氟的嵌入打破了平移对称性并引入了长程无序。这些结果突出了电化学作为一种用于固态材料的新型“温和化学”氟化技术的有效性。该过程在室温下进行，此外不需要任何特殊的实验处理。电解介质的选择对于氟的嵌入速率以及材料的劣化至关重要。该技术在著名的La₂CuO₄材料上的成功应用为从其他氧化物进行进一步合成提供了基础。
