Polyol
More than one alcohol group can exist in one molecule.
Glycerol is a triol because it has three alcohol functional groups.
Molecular compound · triol
Glycerol
C₃H₈O₃
Glycerol is C₃H₈O₃, a three-carbon triol. Its condensed structure HOCH₂–CHOH–CH₂OH places one hydroxyl group on each carbon.
Name note: glycerol is the compound name; glycerin/glycerine is often used for glycerol-containing commercial material and can include water or impurities.
Essentials
Three –OH groups define glycerol as a triol.
The condensed structure is much more informative than C₃H₈O₃ because it shows one hydroxyl group on each carbon of the three-carbon chain.
Detail
The 2D structure fixes the chain connectivity while leaving conformations free.
Single C–C and C–O bonds allow many three-dimensional conformations; the flat drawing is a connectivity map, not a rigid molecular pose.
Flexibility
Three hydroxyl groups do not lock the molecule flat.
Rotation about single bonds produces many conformations while preserving connectivity.
Understand
Multiple –OH groups create many hydrogen-bonding opportunities.
Each hydroxyl can participate in donor and acceptor interactions, producing a dense intermolecular hydrogen-bond network in glycerol and in mixtures with water.
Structure → viscosity
Strong, numerous intermolecular interactions resist molecular rearrangement.
Hydrogen bonding is one major contributor to glycerol's high viscosity, alongside molecular size and shape.
Reference identifiers
Names and identifiers that pin down the chemical identity.
| Formula | C₃H₈O₃ |
|---|---|
| CAS Registry Number | 56-81-5 |
| PubChem CID | 753 |
Advanced
Push past the first model without losing the simple picture.
Is glycerol chiral?
Unsubstituted glycerol is achiral because the two terminal CH₂OH groups are equivalent.
Does three –OH groups mean three times the hydrogen bonding of methanol?
No. Interaction counts and strengths are not linearly additive; geometry, concentration and network organization matter.
Is glycerin always chemically pure glycerol?
Not necessarily. Commercial naming can refer to glycerol-rich material with specified water or impurity content.
Constituent elements