Stems, roots, bases

In a number of IUPAC publications, the entities that are referred to as “stems” include

• Latin stems such as ‘argent’, ‘aur’, ‘cupr’, ‘ferr’, etc. used before ‘ide’ or ‘ate’ in anion names [1];
• Stem name ‘carotene’ in nomenclature of carotenoids [2, rule 2];
• Stem ‘calci-’ in nomenclature of vitamin D [3];
• Stem ‘retin-’ in nomenclature of retinoids [4];
• In carbohydrate nomenclature, stem names that designate the chain length of the sugar, e.g. ‘pent-’, ‘hex-’, ‘hept-’ etc. [5];
• Stems such as ‘irene’, ‘irane’, ‘epine’ etc. in Hantzsch-Widman (H-W) nomenclature [6];
• Stem name ‘phosphatidic acid’ [7].

Before we go any further, we have to distinguish between the terms “root”, “stem” and “base”, which are often used interchangeably even in linguistic literature.

Suffixes — or combining forms?

In a number of IUPAC publications, the entities that are referred to as “suffixes” include

• Suffix for the principal characteristic group, such as ‘-amine’, ‘-one’ or ‘-oic acid’ [1];
• Suffixes indicating charge [2, p. 5];
• Suffixes indicating loss or addition of one or more hydrogens from/to parent hydrides, e.g. ‘-ium’, ‘-ylium’, ‘-ide’ or ‘-uide’ [2, p. 105] ;
• Suffixes ‘yl’, ‘ylidene’ or ‘ylidyne’ in the names of radicals and substituent groups [2, p. 108];
• Subtractive suffixes ‘ene’ and ‘yne’ [3];
• Composite suffixes [4, p. 82 ] aka combined suffixes [2, p. 251] that contain multiplicative prefixes, as in ‘diyl’ or ‘triylium’;
• Suffixes ‘quinone’, ‘quinol’, ‘chromenol’ and ‘chromanol’ in names of quinones [5].