LiMo8O10: Polar Crystal Structure with Infinite Edge-Sharing Molybdenum Octahedra

Zachary T Messegee; Philippe Gall; Hari Bhandari; Peter E Siegfried; Chang-Jong Kang; Benjamin Chen; Carl R Conti 3rd; Banghao Chen; Mark Croft; Qiang Zhang; Syed N Qadri; Joseph Prestigiacomo; Nirmal J Ghimire; Patrick Gougeon; Xiaoyan Tan

doi:10.1021/acs.inorgchem.2c01917

LiMo₈O₁₀: Polar Crystal Structure with Infinite Edge-Sharing Molybdenum Octahedra

Inorg Chem. 2022 Sep 5;61(35):13924-13932. doi: 10.1021/acs.inorgchem.2c01917. Epub 2022 Aug 22.

Authors

Zachary T Messegee¹, Philippe Gall², Hari Bhandari^{3

4}, Peter E Siegfried^{3

4}, Chang-Jong Kang^{5

6}, Benjamin Chen⁷, Carl R Conti 3rd⁷, Banghao Chen⁷, Mark Croft⁸, Qiang Zhang⁹, Syed N Qadri¹⁰, Joseph Prestigiacomo¹⁰, Nirmal J Ghimire^{3

4}, Patrick Gougeon², Xiaoyan Tan¹

Affiliations

¹ Department of Chemistry and Biochemistry, George Mason University, Fairfax, Virginia 22030, United States.
² Sciences Chimiques de Rennes, UMR 6226 CNRS─INSA─Université de Rennes 1, Avenue du Général Leclerc, Rennes 35042, France.
³ Department of Physics and Astronomy, George Mason University, Fairfax, Virginia 22030, United States.
⁴ Quantum Science and Engineering Center, George Mason University, Fairfax, Virginia 22030, United States.
⁵ Department of Physics, Chungnam National University, Daejeon 34134, Republic of Korea.
⁶ Institute of Quantum Systems, Chungnam National University, Daejeon 34134, Republic of Korea.
⁷ Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States.
⁸ Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States.
⁹ Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.
¹⁰ U.S. Naval Research Laboratory, Washington, District of Columbia 20375, United States.

PMID: 35993886
DOI: 10.1021/acs.inorgchem.2c01917

Abstract

Polycrystalline LiMo₈O₁₀ was prepared in a sealed Mo crucible at 1380 °C for 48 h using the conventional high-temperature solid-state method. The polar tetragonal crystal structure (space group I4₁md) is confirmed based on the Rietveld refinement of powder neutron diffraction and ⁷Li/⁶Li solid-state NMR. The crystal structure features infinite chains of Mo₄O₅ (i.e., Mo₂Mo_4/2O_6/2O_6/3) as a repeat unit containing edge-sharing Mo₆ octahedra with strong Mo-Mo metal bonding along the chain. X-ray absorption near-edge spectroscopy of the Mo-L₃ edge is consistent with the formal Mo valence/configuration. Magnetic measurements reveal that LiMo₈O₁₀ is paramagnetic down to 1.8 K. Temperature-dependent resistivity [ρ(T)] measurement indicates a semiconducting behavior that can be fitted with Mott's variable range hopping conduction mechanism in the temperature range of 215 and 45 K. The ρ(T) curve exhibits an exponential increase below 5 K with a large ratio of ρ_1.8/ρ₃₀₀ = 435. LiMo₈O₁₀ shows a negative field-dependent magnetoresistance between 2 and 25 K. Heat capacity measurement fitted with the modified Debye model yields the Debye temperature of 365 K.