) to the orthorhombic polar structure, space group Cmc21, often described as ice phase XI (Line & Whitworth, 1996; Jackson et al., 1997).+In memory of Dr Igor Goncharenko (1965-2007).
1The SI pressure units, Pascal = Newton metre-2 (Pa = N m-2), are used in this paper. The atmospheric pressure at sea level is approximately 0.1 MPa = 1 bar.
2Ice Ih doped with KOH at 72 K transforms following the onset of the H-atom ordering (Kawada, 1972) to the orthorhombic polar structure, space group Cmc21, often described as ice phase XI (Line & Whitworth, 1996; Jackson et al., 1997).
3Percy Williams Bridgman (1882-1961), a Professor of Harvard University in Cambridge, Massachusetts, dedicated his research to high-pressure physics, thermodynamics and philosophy; in 1946, he was awarded the Nobel Prize for his achievements in high-pressure research.