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Mechanical Properties of Dense Zeolitic Imidazolate Frameworks (ZIFs): A High‐Pressure X‐ray Diffraction, Nanoindentation and Computational Study of the Zinc Framework Zn(Im) 2 , and its LithiumBoron Analogue, LiB(Im) 4
Author(s) -
Bennett Thomas D.,
Tan JinChong,
Moggach Stephen A.,
Galvelis Raimondas,
MellotDraznieks Caroline,
Reisner Barbara A.,
Thirumurugan A.,
Allan David. R.,
Cheetham Anthony K.
Publication year - 2010
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201001415
Subject(s) - nanoindentation , zeolitic imidazolate framework , bulk modulus , hydrostatic pressure , materials science , crystallography , diffraction , zinc , lithium (medication) , x ray crystallography , imidazolate , modulus , chemistry , thermodynamics , composite material , inorganic chemistry , metallurgy , metal organic framework , physics , adsorption , optics , medicine , endocrinology
The dense, anhydrous zeolitic imidazolate frameworks (ZIFs), Zn(Im) 2 ( 1 ) and LiB(Im) 4 ( 2 ), adopt the same zni topology and differ only in terms of the inorganic species present in their structures. Their mechanical properties (specifically the Young’s and bulk moduli, along with the hardness) have been elucidated by using high pressure, synchrotron X‐ray diffraction, density functional calculations and nanoindentation studies. Under hydrostatic pressure, framework 2 undergoes a phase transition at 1.69 GPa, which is somewhat higher than the transition previously reported in 1 . The Young’s modulus ( E ) and hardness ( H ) of 1 ( E ≈8.5, H ≈1 GPa) is substantially higher than that of 2 ( E ≈3, H ≈0.1 GPa), whilst its bulk modulus is relatively lower (≈14 GPa cf. ≈16.6 GPa). The heavier, zinc‐containing material was also found to be significantly harder than its light analogue. The differential behaviour of the two materials is discussed in terms of the smaller pore volume of 2 and the greater flexibility of the LiN 4 tetrathedron compared with the ZnN 4 and BN 4 units.