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| Section2 = }} Lithium superoxide (LiO2) is an inorganic compound which has only been isolated in matrix isolation experiments at 15-40 K.〔Bryantsev, V.S.; Blanco, M.; Faglioni, F. Stability of Lithium Superoxide LiO2 in the Gas Phase: Computational Study of Dimerization and Disproportionation Reactions. ''J. Phys. Chem.'' A, 2010, ''114'' (31), 8165–816.〕 It is an unstable free radical that has been analyzed using infrared (IR), Raman, electronic, electron spin resonance, soft X-ray spectroscopies, and a variety of theoretical methods.〔 ==Structure== Experimental studies indicate that the LiO2 molecule contains highly ionic bonds.〔Andrews, L. Infrared Spectrum, Structure, Vibrational Potential Function, and Bonding in the Lithium Superoxide Molecule LiO2. ''J. Phys. Chem''. 1969, ''50'', 4288.〕 Eighteen different values were attained using six isotopic species. This indicated that the force constant between the two oxygen atoms corresponds with the constant found for the O2− ion. Studies indicate that there is little to no covalent character in the LiO2 molecule. The bond length for the O-O bond was determined to be 1.34 Å. Using a simple crystal structure optimization, the Li-O bond was calculated to be approximately 2.10 Å.〔Lau, K.C.; Curtiss, L.A. Density Functional Investigation of the Thermodynamic Stability of Lithium Oxide Bulk Crystalline Structures of Oxygen Pressure. ''J. Phys. Chem.'' 2011, ''115'' (47), 23625-23633.〕 Lithium superoxide is extremely reactive because of the odd electron present in the π * molecular orbital.〔Lindsay, D.M.; Garland, D.A. ESR Spectra of Matrix-Isolated LiO2. ''J. Phys. Chem.'' 1987, ''91''(24), 6158-6161.〕 There have been quite a few studies regarding the clusters formed by LiO2 molecules. The most common dimer has been found to be the cage isomer. Second to it is the singlet bypyramidal structure. Studies have also been done on the chair complex and the planar ring, but these two are less favorable, though not necessarily impossible.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Lithium superoxide」の詳細全文を読む スポンサード リンク
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