Definition
The dominant seventh chord (V7) is the major triad on the V degree with the addition of a minor seventh: in C major G–B–D–F. It contains the tritone B–F between the leading tone and the fourth degree, which asks to resolve to the tonic: for this reason it is the most directional chord of the key. The same chord exists identically in C minor, where it is obtained with the leading tone of the harmonic minor.
The notes with tendency
| Note of the V7 | In C | Regular motion |
|---|---|---|
| Root | G | to C (bass) or stays G (inner voices) |
| Third (leading tone) | B | rises to C |
| Fifth | D | falls to C or rises to E |
| Seventh | F | falls to E |
Root position: complete and incomplete
- Complete V7 → incomplete I: if the V7 has all four notes, resolving regularly the tonic will have the root tripled and the third, without fifth (C–C–C–E).
- Incomplete V7 → complete I: omitting the fifth of the V7 and doubling the root (G–G–B–F) gives a complete tonic.
- In the inner voices the leading tone can fall to the fifth of the tonic (B → G) to complete the chord; in the soprano it must rise.
The inversions
| Inversion | Figure | Bass in C | Typical resolution |
|---|---|---|---|
| First | V6/5 | B | → I (the bass rises to C) |
| Second | V4/3 | D | → I (bass D → C) or I6 (bass D → E) |
| Third | V4/2 | F | → I6 (the bass falls to E) |
The inversions are used complete, with all four notes.
Permitted exception: in the V4/3 → I6 motion, with the bass rising D → E, the seventh may rise F → G, because it moves in parallel tenths with the bass and avoids doubling the third.
Practical rules
- The seventh is prepared (same note in the preceding chord, typical of the Baroque style) or enters by step or as a passing note (G–F in the soprano over the V).
- The seventh in the bass (V4/2) forces the bass to fall: after a V4/2 comes almost always a I6.
- In minor the leading tone must be altered (B natural in C minor, G# in A minor).
- If another voice takes the resolution note of the seventh (for example the bass goes to E in V7 → I6), the seventh may rise.
Common mistakes
- Making the seventh rise in root position.
- Doubling the leading tone or the seventh.
- Leaping to the seventh from above by a wide leap without preparation.
- Writing a complete V7 that resolves to a complete tonic: inevitably some voice will make an incorrect leap or parallel fifths will arise.
Examples
- Bach, Prelude in C major (Well-Tempered Clavier, I): in the third bar a G7 in first inversion (V6/5, B in the bass) resolves to the C of the next bar.
- Mozart, “Eine kleine Nachtmusik”: the opening theme arpeggiates the tonic chord and then the dominant seventh chord.
- Strauss, “The Blue Danube”: the waltz theme alternates tonic and dominant seventh.
- Folk and country: very many songs rest on just I, IV, and V7.
How to use it in composition
- The inversions of the V7 allow stepwise bass lines (C–B–C with V6/5, C–D–E with V4/3, F–E with V4/2): use them to avoid leaps in the bass.
- For a strong close use the V7 in root position with the seventh falling to the third of the tonic.
- In pads and pop arrangements, the F → E descent (seventh → third) is the most effective link between dominant and tonic.
Exercise
- Write in A major: I – V6/5 – I – V4/3 – I6 – IV – V4/2 – I6 – V7 – I.
- Resolve a complete V7 and an incomplete one in four voices in Eb major.
- In D minor write the four inversions of the V7 with their resolutions.
Connections
Seventh chords; The qualities of seventh chords; Perfect and imperfect authentic cadence; Irregular resolutions of the dominant; Secondary dominants; The jazz ii–V–I.