The C♭ Diminished 7th chord is a four-note chord made up of C♭, E♭♭, G♭♭, and A♭. It is built from a root, minor third, diminished fifth, and diminished seventh.
Construction
C♭ Diminished 7th = Root + Minor 3rd + Diminished 5th + Major 6th = C♭ · E♭♭ · G♭♭ · A♭
| Note | Interval | Degree |
|---|---|---|
| C♭ | Root | 1 |
| E♭♭ | Minor 3rd | ♭3 |
| G♭♭ | Diminished 5th | ♭5 |
| A♭ | Major 6th | 6 |
C♭ Diminished 7th Inversions
| Position | Notes |
|---|---|
| Root Position | C♭ – E♭♭ – G♭♭ – A♭ |
| 1st Inversion | E♭♭ – G♭♭ – A♭ – C♭ |
| 2nd Inversion | G♭♭ – A♭ – C♭ – E♭♭ |
| 3rd Inversion | A♭ – C♭ – E♭♭ – G♭♭ |
Key Signature
A Diminished 7th chord is built from symmetrical or ambiguous intervals, so it doesn’t belong to a single key and has no key signature of its own.
Same Notes, Other Names
The notes C♭ – E♭♭ – G♭♭ – A♭ aren’t exclusive to this chord. Depending on which note is the bass and how the chord functions, the same pitches also spell the following:
C♭ Diminished 7th — Frequently Asked Questions
What is the C♭ Diminished 7th chord on piano?
The C♭ Diminished 7th chord contains the notes C♭ – E♭♭ – G♭♭ – A♭. On piano, play these notes together to sound the chord.
What notes are in the Cb Diminished 7th chord?
The Cb Diminished 7th chord (Cbdim7) contains four notes: Cb (root), Ebb (minor third, enharmonically D), Gbb (diminished fifth, enharmonically F), and Bbbb (diminished seventh, enharmonically Ab). This is the enharmonic equivalent of Bdim7.
How does Cb Diminished 7th differ from Cb Diminished?
Cb Diminished is a three-note triad. Cb Diminished 7th adds the diminished seventh, completing the symmetrical four-note structure. In practice, Bdim7 is the preferred spelling.
Why is the Diminished 7th chord symmetrical?
Cbdim7 contains the same pitches as Ddim7, Fdim7, and Abdim7 — all inversions of the same four notes. Only three unique dim7 chords exist in total.
How is Cb Diminished 7th used in music?
Cbdim7 is the enharmonic equivalent of Bdim7, which functions as the vii°7 in C Major. In practice, musicians write Bdim7. The Cb spelling appears in extreme flat-key theoretical contexts.
What songs use Diminished 7th chords?
Diminished 7th chords appear in Michelle (Beatles), throughout Chopin and Beethoven, and in jazz standards. Whether spelled Cbdim7 or Bdim7, the sound is identical.
How many unique Diminished 7th chords exist?
Only three. Cbdim7 shares its notes with Bdim7, Ddim7, Fdim7, and Abdim7. All 12 roots map to just three distinct sounds.