Pauling says in almost all hydrogen bonds the hydrogen atom is nearer to one of the two adjacent electronegative atoms (oxygen) than to the other. In ice, for example, the distance between two hydrogen-bonded oxygen atoms is 2.76 (a), and the proton has been shown by neutron diffraction to be 1.00 (a) from one oxygen atom and 1.76 (a) from the other.
Property - Water (Liquid) Ice (Solid, Ice Ih) Water (High Pressure, Ice VI)
Oxygen-Oxygen Distance~2.8 Å~2.76 Å~2.52 Å (approx.)
H-O-H Angle~104.5°~109.5°Varies, but structure is denser and more compact
Hydrogen Bond Length~1.8 Å (average)1.00 Å and 1.76 ÅShorter than in Ice Ih
Structure Irregular, dynamicHexagonal latticeTetragonal lattice
Bonding Transient hydrogen bondsStable hydrogen bondsStable hydrogen bonds
Pressure AtmosphericAtmospheric>1.1 GPa
The amount of partial ionic character expected for the O—H bond from the electronegativity difference of the atoms is 39%. The hydrogen bond in ice can be described as involving resonance among the three structures A, B and C:
A = O—H :O 61%
B = O: H+ :O 34%
C = O: H—O 5%
where the dash represents a pure covalent bond.