title: High pressure behaviour and elastic properties of a dense inorganic-organic framework.
abstract: The high pressure behaviour of a cubic dense inorganic-organic framework [DABCOH2(2+)][K(ClO4)3] (DABCOH2(2+) = diazabicyclo[2.2.2]octane-1,4-diium) has been systematically studied via synchrotron X-ray powder diffraction, over the range of 0-3.12 GPa. The framework [DABCOH2(2+)][K(ClO4)3] shows a more rigid response, with a bulk modulus of 30(1) GPa and an axial compressibility of 7.6(4) × 10(-3) GPa(-1), compared with ZIF-8 and the dense hybrid solar cell perovskite CH3NH3PbI3. Density functional theory calculations reveal that the structural change in [DABCOH2(2+)][K(ClO4)3] is attributed to the contraction of the KO12 polyhedra, which consequently results in the rotation of the perchlorate linkers and synergistic movement of the DABCOH2(2+) guest. Further extensive theoretical calculations of full elastic tensors give full mapping of the Young's moduli, shear moduli and Poisson's ratios of [DABCOH2(2+)][K(ClO4)3], which are in the range of 31.6-36.6, 12.3-14.6 GPa and 0.2-0.32, respectively. The Young's and shear moduli of [DABCOH2(2+)][K(ClO4)3] are larger than those of cubic MOF-5, ZIF-8 and CH3NH3PbI3. In addition, the narrow range of Poisson's ratios in [DABCOH2(2+)][K(ClO4)3] indicates its very isotropic nature in response to biaxial stress.
authors.affiliation: School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China. wl276@hust.edu.cn and Department of Physics and Mechanical & Electrical Engineering, Hubei University of Education, Wuhan 430205, China.
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Feng
authors.affiliation: Center for Crystal R&D, Key Lab of Functional Crystals and Laser Technology of Chinese Academy of Sciences, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China. zslin@mail.ipc.ac.cn.
authors.forename: Xingxing
authors.initials: X
authors.lastname: Jiang
authors.affiliation: School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China. wl276@hust.edu.cn.
authors.forename: Wenjuan
authors.initials: W
authors.lastname: Wei
authors.affiliation: Center for Crystal R&D, Key Lab of Functional Crystals and Laser Technology of Chinese Academy of Sciences, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China. zslin@mail.ipc.ac.cn.
authors.forename: Pifu
authors.initials: P
authors.lastname: Gong
authors.affiliation: Center for Crystal R&D, Key Lab of Functional Crystals and Laser Technology of Chinese Academy of Sciences, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China. zslin@mail.ipc.ac.cn.
authors.forename: Lei
authors.initials: L
authors.lastname: Kang
authors.affiliation: School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China. wl276@hust.edu.cn.
authors.forename: Zhihua
authors.initials: Z
authors.lastname: Li
authors.affiliation: Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yanchun
authors.initials: Y
authors.lastname: Li
authors.affiliation: Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Li
authors.affiliation: School of Earth and Space Sciences, Peking University, Beijing 100871, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Wu
authors.affiliation: Center for Crystal R&D, Key Lab of Functional Crystals and Laser Technology of Chinese Academy of Sciences, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China. zslin@mail.ipc.ac.cn.
authors.forename: Zheshuai
authors.initials: Z
authors.lastname: Lin
authors.affiliation: School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China. wl276@hust.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China. wl276@hust.edu.cn and Laboratory for Optical Information Technology, Wuhan Institute of Technology, Wuhan 430205, China.
authors.forename: Peixiang
authors.initials: P
authors.lastname: Lu