The “On the Cover” information in Powder Diffraction, Volume 34, Issue 1 was incorrect.

It should read “On the Cover: This Issue contains the first of a Special Section of papers related to the crystallography, structure and properties of Metal Organic Framework (MOF) materials. This Issue's cover is from the technical article by Matthew Lawson et al. It shows the atomic structure of the porous MnO₂ Octahedral Molecular Sieve, OMS-5. The figure shows the tunnels containing the CO₂ molecules (O in red, C in black, Mn in purple and Na in gold) in two orientations: (a) head-to-head and (b) stacked. The formation energy for the head-to-head orientation was determined to be smaller than that for the stacked orientation indicating that the CO₂ molecules in OMS-5 prefer to align head-to-head in the tunnel.”