Figure 6. Fraction of molecules in the low-density state.

The fraction x is shown for the two-state model at 0.1 MPa, in the case of an athermal solution (solid) and an ideal solution (dotted). The dashed curve is the fraction of four-coordinated water molecules, i.e., the fraction of water molecules with four neighbours, for mW water simulations performed by Moore and Molinero⁴⁵ (see Supplementary Section 6). The temperature is scaled by the temperature of maximum density T_MD (250 K for the mW model and 277 K for real water).