Table 4. Crystal Structure and Density of Various Ice Forms^a.

ice form	crystal structure	density [g cm–3]
Ih	hexagonal	0.92
Ic	cubic	0.93
II	rhombohedral	1.17
III	tetragonal	1.14
IV	rhombohedral	1.27
V	monoclinic	1.23
VI	tetragonal	1.31
VII	cubic	1.50
VIII	tetragonal	1.46
IX	tetragonal	1.16
X	cubic	2.51
XI	orthorhombic	0.92
XII	tetragonal	1.29
XIII	monoclinic	1.23
XIV	orthorhombic	1.29
XV	pseudoorthorhombic	1.30
XVI	cubic	0.81

^aData collected from ref (37).