Ilia Valov opened discussion of the paper by Tony Kenyon: I saw that your device structures looked very similar to the device structures Elia Ambrosi showed yesterday (DOI: 10.1039/C8FD00106E). Your electrode was Mo, his was C. You didn’t discuss the mechanism, do you suppose it’sa similar mechanism? Also the stoichiometry, do you get a similar stoichiometry as that for his samples, ie 1: 1?Tony Kenyon answered: There are some key differences in our device structure. First, Elia’s devices (DOI: 10.1039/C8FD00106E) were 70 nm in diameter and sub-10 nm thickness. Our devices were microns across, with column diameters in the range of 70 nm. It may well be, then, that Elia’s devices do not contain column boundaries. We may expect different switching mechanisms in the two different types of sample. Then there is the issue of electrodes. As you say, our bottom electrode is Mo, which may well play a role …