Chromatic Mediants Explained: Major Chords a Third Away
A chromatic mediant is a triad a third from the tonic that lies outside the key. For C major the four are E♭, E, A♭ and A major, and each one shares a note with the C triad.
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A chromatic mediant is a major or minor triad, of the same quality as the tonic, whose root lies a major or minor third from the tonic and which is not diatonic to the key. In C major there are four: major triads on E♭, E, A♭ and A. Each one shares exactly one note with the C major triad, C, E and G, and brings in two pitches that triad does not contain.
Four chords, one shared note each
The table lists each mediant, its distance from C, and the note it shares with the C major triad.
| Chord | Notes | Distance from C | Shared with C, E, G | Not in C, E, G |
|---|---|---|---|---|
| E♭ major | E♭ G B♭ | minor third up | G | E♭, B♭ |
| E major | E G♯ B | major third up | E | G♯, B |
| A♭ major | A♭ C E♭ | major third down | C | A♭, E♭ |
| A major | A C♯ E | minor third down | E | A, C♯ |
The count depends on the reference. Against the full C major scale, E major shares two notes, E and B, and A major shares two, A and E, because B and A are scale tones of C major. The one-note rule holds for the triad, which is the sense used here.
None of the four is diatonic. The diatonic triads of C major are C, D minor, E minor, F, G, A minor and B diminished, so E major and A major are not in the key, and E♭ and A♭ are not either. The mediant relation is a third, but the key membership is what makes the chord chromatic.
Sharp mediants brighten, flat mediants darken
The sharp mediants raise a note of C. E major raises G to G♯, which is the raised fifth of C. A major raises C to C♯, the raised tonic. Both are a semitone above the note they replace, and both sit higher against the tonic than the diatonic note does. The upward lean is the usual explanation for the brighter sound.
The flat mediants lower notes of C. E♭ major lowers E to E♭, the flat third, and brings in B♭, the lowered seventh. A♭ major lowers A to A♭, the flat sixth, and E to E♭. Each lowered pitch sits a semitone below the diatonic note, so it leans downward, and the chord sounds darker.
The spelling follows the key, not the sound. A♭ and G♯ are the same pitch in equal temperament, so the choice between them is a question of context. In C major the mediant is written as A♭ major, because the surrounding notes are flat.
One note held through a change of root
In a chain of mediants, one note can sit still while the chords move beneath it. The chain C, E♭, G shares a note through all three triads: G is in C major, in E♭ major and in G major. Keep the G in the top voice, and the bass rises from C to E♭ to G underneath it.
The bass rises a minor third from C to E♭, then a major third from E♭ to G. Neither move is a fifth, so the bass gives no dominant pull, and the G in the top voice is the only link the ear needs. The chain can end on C through the same G. Once G major is reached, the G in the top voice is its root, and the bass falls a fifth to C. That is a dominant to tonic close, the ordinary route back to the key, and the G that carries the chain is already in place.
Chains by major third
A chain of mediants can move by thirds with a pivot in the upper voice. C to E to A moves the bass up a major third, then a perfect fourth. E is in C major, in E major and in A major, so it can stay in the top voice through all three chords.
C to A♭ to E is different. C is shared by the first two chords, but A♭ major and E major share no pitch at all. The second step has no pivot, so the change is heard as a break, and the bass carries the progression on its own. Playing the two chains in turn makes the difference clear.
The C to A♭ to E chain is a useful test of what a mediant does. The first step is held together by a note, and the second is not. A composer who wants the pivot to hold must check each step, not only the chain as a whole.
Why the return to C is the hard part
None of the four chords is built on G, the dominant of C. None of them has the root motion of V to I, so none pulls toward C the way a dominant does. The return to C must come from a common tone, from a deliberate dominant, or from a change of key that makes the new chord a tonic.
This is why chromatic mediants usually appear in a passage that is already shaped by a clear key, or in music that will change key. Romantic composers used mediant relations often, and the same sound is familiar from film scores. The mediant is a way to change colour and key without the strong bass motion of a cadence, and that is also why a progression built on mediants can sound as if it has no direction.
The borrowed chords article covers E♭ and A♭ in another way. Those two are the III and VI chords of C minor, so they can be called borrowed. E and A major are not in C minor, so the mediant is the only label that describes them. The label depends on which question is being asked, the source of the chord or its relation to the tonic.
Where this misleads people
The first error is to call any chord a third away a mediant. The quality matters: the chord must match the tonic. The diatonic chords on E and A in C major are minor, so E minor and A minor are diatonic and not chromatic mediants. The major triads on the same roots are chromatic.
The second error is to treat the label as a description of function. A mediant describes the relation of two roots and the key membership of the chord. It does not say what the chord does in the phrase. The same chord may be a mediant in one passage, a tonicization in another, and a borrowed chord in a third.
The third error is to expect the mediant to lead to a dominant. Many mediant progressions have no dominant at all, and a listener who waits for V to I may hear the phrase as unfinished. That is not a fault. It is the reason the device is used, and the phrase is finished by a different route.
What to do with it
Write a four-bar phrase in C that goes to E♭ and returns through the G, using C, E♭, G and C as the chords. Then write one that goes to A major and returns through the E. In both cases hold the shared note in the top voice and check that it stays put. Sing it, then play it.
Next, take A♭ major as a tonic and find its four chromatic mediants. C major is one, a major third up, and it shares C with A♭. B major is a minor third up. F major is a minor third down, and E major is a major third down. Check which of them share a pitch with the A♭ triad, and remember that G♯ and A♭ are the same pitch. B major shares none, which shows that the one-note count belongs to C major and is not a rule for every mediant. The modulation strategies article shows how mediant chains can be turned into a change of key, and the triads article gives the inversions you need to voice each chord in a smooth position.
Questions
What is a chromatic mediant?
A major or minor triad, of the same quality as the tonic, whose root lies a major or minor third from the tonic and which is not diatonic to the key. In C major the chromatic mediants are major triads on E♭, E, A♭ and A.
How do you return from a chromatic mediant to the tonic?
Usually through a note the two chords share, or through a dominant chord. From E♭ major back to C major, the G belongs to both triads, so it can be held while the bass moves.
Is E minor a chromatic mediant of C major?
No. E minor is diatonic to C major as the iii chord. The chromatic mediant on E is E major, which contains G sharp, a note that C major does not have.
Are E♭ and A♭ major borrowed chords in C major?
They can be described that way. They are the III and VI chords of C minor, so they come from the parallel minor. E and A major are not in C minor, so for those two the mediant label is the only one that fits.
