What do we call diols with hydroxyl groups on adjacent carbons?

Diols with hydroxyl (–OH) groups positioned on adjacent carbons are referred to as vicinal diols. The term "vicinal" specifically denotes that the hydroxyl groups are located on neighboring carbon atoms in the molecular structure. This distinction is important in organic chemistry as it helps in identifying the specific arrangement of functional groups, which can influence the compound's reactivity and physical properties.

In contrast, the term "geminal" refers to diols where both hydroxyl groups are attached to the same carbon atom, which represents a different structural concept. Non-polar alcohols generally refer to alcohols that lack significant polarity, usually due to the presence of larger hydrocarbon chains, and are not specifically descriptive of the arrangement of hydroxyl groups. Aromatic diols are compounds that contain hydroxyl groups attached to an aromatic ring and, again, do not pertain to the adjacency of the hydroxyl groups on straight-chain carbon atoms.

Therefore, the use of "vicinal" is appropriate for describing diols where the hydroxyl groups are adjacent, making this term essential for clear communication about organic structures in chemistry.