5 research outputs found
Silver Oxalate: Mechanical Properties and Extreme Negative Mechanical Phenomena
9 pags., 7 figs., 1 tab.The crystal structure and mechanical properties of silver oxalate, Ag2C2O4,
are determined using first-principles solid-state methods. The set of
calculated mechanical properties include the bulk modulus and its pressure
derivatives, the Young and shear moduli, the Poisson’s Ratio and the ductility,
hardness, and anisotropy indices. Silver oxalate is a highly anisotropic brittle
material possessing a small bulk modulus of 9.6 GPa. It displays the
negative Poisson’s ratio (NPR) phenomenon, the value of the lowest NPR
having a very large magnitude, −1.27. Besides, it exhibits the most extreme
form of the negative linear compressibility (NLC) phenomenon found to date.
Silver oxalate displays anisotropic NLC for external pressures in the range
−0.1 to −2.4 GPa directed along the [010] crystallographic direction and
isotropic NLC for isotropic pressures in the range −0.51 to 13.4 GPa. The
lowest value of the negative compressibility, −831.9 ± 10 TPa−1, is found for
an isotropic pressure of −0.16 GPa. The absolute value of the computed
lowest NLC is extremely large, about three times larger than the absolute
value of the lowest NLC found so far. The NLC pressure range is also very
wide, its width being more than two times the largest range found to dateSupercomputer time by the CTI-CSIC center is greatly acknowledgedPeer reviewe