Definition
Just as every diatonic chord can have its own secondary dominant (V/x), it can also have its own secondary leading-tone chord: a diminished triad, a diminished seventh, or a half-diminished seventh built a half step below the arrival chord. In C major, the vii°7/V is F#–A–C–Eb, which resolves to G. These chords have the same function as secondary dominants, but with a tenser, more chromatic sound, and above all with voice leading by half steps.
How they are built
- Identify the chord to be tonicized (for example V = G).
- Find its leading tone (F#).
- Build on it the diminished triad (F#–A–C) or the diminished seventh (F#–A–C–Eb) or half-diminished seventh (F#–A–C–E).
Table in C major
| Arrival chord | vii°7/x | viiø7/x (only if the arrival is major) |
|---|---|---|
| ii (Dm) | C#–E–G–Bb | — |
| iii (Em) | D#–F#–A–C | — |
| IV (F) | E–G–Bb–Db | E–G–Bb–D |
| V (G) | F#–A–C–Eb | F#–A–C–E |
| vi (Am) | G#–B–D–F | — |
The secondary half-diminished seventh is used only before major chords, because its seventh belongs to the major scale of the arrival chord; before minor chords the diminished seventh is used, whose seventh coincides with the sixth degree of their minor scale.
Resolution
- The leading tone (root of the chord) rises a half step to the root of the arrival.
- The seventh falls by step.
- The diminished fifth (between root and fifth) closes by falling; in the vii°6/x triad the third is usually doubled.
- The vii°7/V often goes to the cadential six-four (F#°7 → C/G → G7 → C). In this case the seventh Eb does not fall but rises to the E of the 6/4: for this reason many composers write it as D#, showing the ascending direction.
Practical rules
- Write the accidentals according to function: the vii°7/V in C is F#–A–C–Eb, not Gb–A–C–Eb.
- Use the vii°7/x on the weak beat and the arrival on the strong beat.
- As with secondary dominants, avoid cross-relations: the altered note (F#) should, if possible, be in the same voice as the preceding natural F.
Common mistakes
- Using the viiø7/x before a minor chord (for example G#–B–D–F# before Am): the F# contradicts the key of A minor.
- Making the secondary leading tone fall.
- Doubling the root (the leading tone) in the secondary diminished triad.
Examples
- Bach chorales: the vii°7/V and the vii°7/ii appear continually as chromatic passing chords, often in first inversion.
- Beethoven, “Pathétique” Sonata, introduction: diminished sevenths that tonicize various degrees, charged with dramatic tension.
- Rhythm changes and jazz standards: C – C#°7 – Dm7 – G7 is a vii°7/ii (C#°7) that links I and ii with a chromatic bass.
- Pop and gospel ballads: C – C#°7 – Dm7 and F – F#°7 – C/G are very widespread passing formulas.
How to use it in composition
- To create an ascending chromatic bass, insert a vii°7/x between two diatonic chords: C – C#°7 – Dm, Dm – D#°7 – Em.
- Replacing a V/x with the vii°7/x makes the same progression darker and tenser.
- The vii°7/V followed by the cadential six-four is one of the most expressive cadences of the Classical-Romantic style.
Exercise
- Write in four voices in F major: I – vii°7/ii – ii – vii°7/V – I6/4 – V7 – I.
- Replace two secondary dominants in a progression of your own with the corresponding leading-tone chords.
- Play C – C#°7 – Dm7 – G7 and then C – A7 – Dm7 – G7: describe the difference.
Connections
Secondary dominants and extended dominants; The diminished seventh chord and its uses; Passing, auxiliary, and neighbor diminished chords; Tonicization; The half-diminished seventh chord.