Music Theory for the 21st-Century Classroom

Because there are three versions of the minor scale, there are more than seven diatonic chords in minor. The sixth and seventh scale degrees affect all of the triads except the tonic, making 13 possible diatonic triads in minor.

However, when one analyzes a large amount of tonal music, one finds the following Roman numerals are most commonly used in minor.

Notice that both $\text{VII}$ (the “subtonic triad”) and ${\text{vii}}^{\circ }$ (the “leading-tone triad”) are included.

The subtonic triad regularly occurs in circle of fifth progressions in minor (see Section 9.1) and in rock and pop music (see Section 9.6). The leading-tone triad (${\text{vii}}^{\circ }$) is built on raised $\hat{7}$ and is usually either a passing harmony or has dominant function (see Section 9.4).