The neutron reflectometry measurements investigated herein were previously published by Hollinshead et al. and subsequently re-analysed by McCluskey et al. . These measurements concern the study of a monolayer of DSPC at the air/water interface and were conducted on seven different isotopic contrasts of the phospholipid and water. These contrasts were made up from four phospholipid types; fully-hydrogenated (h-DSPC), head-deuterated (d 13 -DSPC), tail-deuterated (d 70 -DSPC), and fully deuterated (d 83 -DSPC). These were paired with two water contrasts; D 2 O and aircontrast matched water (ACMW, where D 2 O and H 2 O are mixed such that the resulting scattering length density is zero). The pairing of the fully-hydrogenated phospholipid with ACMW was not performed, most likely due to the lack of the scattering available from such a system. Table gives the shorthands that are used in this work to refer to the different contrast pairings investigated. This data analysed in this work was taken at a surface pressure of 30 mN m -1 . Additional details of the data collection may be found in the original publication .