Properties of Amines:

Structure

Amines contain sp³ hybridized nitrogen related to three substituents via three σ bonds. The three substituents can be alkyl, hydrogen, or aryl groups, but at least one of the substituents must be an alkyl or aryl group. If only one such type of group is present, the amine is described as primary. If two groups are exists, the amine is secondary. If three groups are exists, then the amine is tertiary. If the substituents are all alkyl groups, the amine is described as being an alkylamine. If there is at least one aryl group directly linked to the nitrogen, after that the amine is described as an arylamine.

The nitrogen atom comprises four sp³ hybridized orbitals pointing to the corners of a tetrahedron in similar way as a sp³ hybridized carbon atom. Though, one of the sp³ orbitals is occupied through the nitrogen's lone pair of electrons. The meaning of this is that the atoms in an amine functional group are pyramidal in shape. The C-N-C bond angles are about 109? that is consistent with tetrahedral nitrogen. Though, the bond angle is little less than 109? as the lone pair of electrons demands a slightly greater amount of space than σ (sigma) bond.