Extended Dominants (V9, V11, V13)
The dominant chord can be extended further than the usual addition of a 7th (V7). By continuing to add the note a third higher each time, the chord can be changed to V9 (added 9th above the root), V11, and V13. Here are the extended dominant chords in C major and A minor.
In effect, this means that any diatonic note can be added into a dominant chord. The following table shows all the notes in C major, and which dominant chord they belong to:
| C | D | E | F | G | A | B |
| V11 | V | V13 | V7 | V | V9 | V |
In addition, added notes can also be altered chromatically. Two common examples are Vb9 (V with a flat 9th), and Vb13:
Sometimes a dominant chord might be extended with two (or more) additional notes, for example a 7th and an 11th. Only include the highest number in the chord symbol. The following chord includes both an added 7th (F) and 9th (A). The chord is V9.
Extended Dominant at a Cadence
Most Classical and Romantic period music is constructed in phrases which end with a standard cadence. When the bass moves from the dominant to the tonic note, the expected cadence is perfect (V-I).
Sometimes (particularly in Romantic music), there may be additional notes from an extended dominant chord and this might appear confusing, until the structural harmony (cadence) is taken into account. An example is in Schumann’s “Cradle Song” for piano (op.124 no.6):
The key is G major. In bar 14, the boxed chord appears at first sight to be iiib (B minor with a D bass note in the left hand). However, the progression iiib-I is not typical (anywhere, but especially at a cadence). The bass line moves from dominant D in bar 14, to tonic G in bar 15, so the structural harmony is V-I, and the best analysis of the boxed chord is V13a (D-F#-A-B). (The plagal IV-I cadence which follows is an “extra”, for decorative purposes).
Extended dominants are most often seen in root position for this reason (although exceptions do occur).
If you are trying to work out a chord by stacking it in thirds, but find a chord which is not built from thirds, it is quite possible that it is in fact an extended dominant chord. Check to see if it moves to chord I, to verify whether it is.