Stands for "normal" and indicates that a carbon chain is unbranched, such as n-propanol vs. isopropyl alcohol.

ortho-, meta-, para- (o, m, p)

Aromatic ortho meta para.png

The prefixes ortho, meta, and para are all derived from Greek, meaning straight or correct, following or after, and akin to or similar, respectively. The relationship to the current meaning is perhaps not obvious. The ortho description was historically used to designate the original compound, and an isomer was often called the meta compound. For instance, the trivial names orthophosphoric acid and trimetaphosphoric acid have nothing to do with aromatics at all. Likewise, the description para was reserved for just closely related compounds. Thus Berzelius originally called the racemic form of aspartic acid paraaspartic acid (another obsolete term: racemic acid) in 1830. The use of the descriptions ortho, meta and para for multiple substituted aromatic rings starts with Wilhelm Körner in the period 1866–1874 although he chose to reserve the ortho prefix for the 1,4 isomer and the meta prefix for the 1,2-isomer. The current nomenclature (different again from that of Körner) was introduced by the Chemical Society in 1879.[3]

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Glycols AKA Diols

  • Organic compound with two hydroxyl (alcohol) groups.