Explanation on Notation and Arrangement

An absorbing system consists of a chromophore or conjugated chromophores, printed in bold face type in Table I, and an atom or atoms, if any, joined to the chromophore or conjugated chromophores, and sometimes, consists merely of auxochromic atoms. 

Rules determine the notation and sequence of absorbing systems, as mentioned below. 

Rule 1. The more predominant factor in an absorbing system is cited as early as possible. Absorbing systems having a more predominant factor are placed later in the tables. 

For example, CiC predominated over C C as mentioned in Rule 3, and therefore the chromophore of butenyne is denoted such as C C C C (not C C-CiC), and C C precedes C C in the tables. 

Rule 2. The order of increasing predominancy of atoms or elements is as follows  

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