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How many neighboring water molecules surround each oxygen atom in an ice crystal?
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ice
An iceberg in the waters off Greenland.
In an ice crystal, each oxygen atom is surrounded by four neighboring water molecules, which are arranged in a rigid, open tetrahedral lattice.1
Within this structure, the oxygen atom is covalently bonded to two hydrogen atoms, while the other two hydrogen atoms are connected to the oxygen atom via hydrogen bonds formed with its unshared electron pairs. This specific, open configuration is responsible for the fact that ice is less dense than liquid water, which allows ice to float.21