Section 18.2 Secondary Diminished Chords in Major and Minor
Below are the secondary diminished chords that occur in major and minor.
Notice that \(\left.\text{vii}^{\circ}{}\middle/\text{III}\right.\) in minor is not included because it is \(\left.\text{ii}^{\circ}{}\right.\). Notice also that \(\left.\text{vii}^ø{}^{7}\middle/\text{III}\right.\) has no accidentals—it is the same as \(\left.\text{ii}^ø{}^{7}\right.\) but functions differently. The \(\left.\text{ii}^ø{}^{7}\right.\) chord has pre–dominant function and progresses to \(\left.\text{V}\right.\) whereas the \(\left.\text{vii}^ø{}^{7}\middle/\text{III}\right.\) chord progresses to \(\left.\text{III}\right.\).
Minor triads are tonicized by fully diminished seventh chords. Major triads are traditionally tonicized by half diminished seventh chords but can also be tonicized by fully diminished seventh chords.
