Diminished third

[5] In 12-tone equal temperament a diminished third is enharmonic with the major second, both having a value of 200 cents.

However, in meantone tunings with fifths flatter than 700 cents, the diminished third is wider than the major second.

In 19 equal temperament it is in fact enharmonically equivalent to an augmented second, both having a value of 252.6 cents.

In the special case of 17 equal temperament, the chromatic semitone and diminished third are in fact represented by the same interval of 141.18 cents, which allows the minor third to be evenly divided in half.

The complementary interval to the diminished third is the augmented sixth, and the numerous chords of common practice music described as augmented sixth chords thereby contain the diminished third as well.