Figure 6
(a) The pressure dependence of the void volume (Vvoids) of ZnAsp2·1.5H2O (open symbols, dotted lines) and ZnAsp2·2H2O (solid symbols, continuous line) after removing the water molecules from these structures, per one formula unit (Vvoids/Z). The void volume was calculated using the program Mercury (Macrae et al., 2020 ) with a probing-sphere radius of 1.2 Å and 0.1 Å steps. (b) The molecular volume of water (i.e. one H2O molecule in liquid; Bridgman, 1935 ) and ices VI (Kuhs et al., 1984 ) and VII (Bezacier et al., 2014 ) as a function of pressure compared with the difference in molecular volume (Vm = V/Z) between ZnAsp2·2H2O and ZnAsp2·1.5H2O (ΔVm). Δ0 is this difference at 0.1 MPa (see also Fig. S6). |