The Use of Greek Letters to Denote Substituent Positions

In the older literature, considerable use is made of the Greek letters α, β, γ, and so on, to designate successive positions along a hydrocarbon chain. The carbon directly attached to the principal function group is denoted as α, the second carbon is β, and so on down the chain:

The omega (ω) position is sometimes used to designate the last position along the chain regardless of its length. Thus ωω-bromohexanoic acid is 6-bromohexanoic acid. In general, the use of Greek letters in the naming of compounds is to be avoided. Because the usage is widespread, cognizance of the system is important, but systematic naming and numbering systems should be used whenever possible.