We seek to develop new stable MOFs for practical gas separation and request 3 days on WISH to study the preferred binding sites of adsorbed gas molecules (CD4, C2D4 and C2D2) within a series of isostructural MOFs (MFM-190, MFM-191 and MFM-192) with varying functional groups. There are notable differences in the MFM-190 series in adsorption of light hydrocarbons, carbon dioxide and methane under ambient conditions. The high resolution, low background and large d-spacing capabilities of WISH make it ideal for analysing the precise locations of gas molecules within these porous MOFs and to define the preferred orientations of molecules with respect to the binding sites on the pore surface. This study will reveal key structural insights into the role of the pore environment for gas uptake.