Rare-Earth Fluorite-like Li_0.42La_4.58Mo₃O_15.76±δF_0.42±ε Molybdates: Crystal Growth and Atomic Structure

• Published in: Crystals
• Main Authors: Ekaterina I. Orlova, Timofei A. Sorokin, Vladimir B. Kvartalov, Alexander M. Antipin, Nataliya E. Novikova, Elena P. Kharitonova, Nataliya I. Sorokina, Olga A. Alekseeva, Valentina I. Voronkova
• Format: Article
• Language: English
• Published: MDPI AG 2023-06-01
• Subjects: crystal growth; crystal structure; rare-earth molybdates; fluorine-containing molybdates; oxyfluorides; Nd₅Mo₃O₁₆
• Online Access: https://www.mdpi.com/2073-4352/13/7/1009
• ISSN: 2073-4352

Rare-earth fluorine-containing molybdates of the <i>Ln</i>₅Mo₃O_16+δ oxygen–electron conductor family with the LiLa₄Mo₃O₁₅F composition were synthesized for the first time as single crystals by the flux method. An accurate X-ray diffraction analysis of the obtained crystals was carried out at 20 and −183 °C. The LiLa₄Mo₃O₁₅F compound is isostructural to the fluorine-free analogue with a cubic structure (space group <i>Pn</i><inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mover accent="true"><mn>3</mn><mo>¯</mo></mover></semantics></math></inline-formula><i>n</i>). It is shown that lithium atoms replace one of the two positions of lanthanum in the more distorted LaO₈ polyhedron. According to X-ray diffraction analysis, fluorine atoms replace the positions of over-stoichiometric oxygen located in the vast cavities of the structure. So, fluorine anions can promote the interstitial conductivity of F-containing LiLa₄Mo₃O₁₅F molybdates.