Figure 5.

Illustration of the (left) wobbling and (right) hopping motions displayed by CO₂ adsorbed in α-Zn₃(HCOO)₆. The CO₂ wobbles locally upon the hydrogen-based adsorption site through the angle α and hops between adjacent adsorption sites located along the crystallographic b axis at an angle β. Carbons are dark gray, oxygens are red, hydrogens are white, and [ZnO₆] units are purple octahedra. All framework carbons and hydrogens are omitted for clarity except for H1, H5, and H6 and the corresponding carbons. The red and gray dashed lines represent C–O bonds between the carbons and [ZnO₆] units that connect the top and the bottom of the channels. These units are also omitted for clarity.