The A♯ Diminished chord is a three-note chord made up of A♯, C♯, and E. It is built from a root, minor third, and diminished fifth.
Construction
A♯ Diminished = Root + Minor 3rd + Diminished 5th = A♯ · C♯ · E
| Note | Interval | Degree |
|---|---|---|
| A♯ | Root | 1 |
| C♯ | Minor 3rd | ♭3 |
| E | Diminished 5th | ♭5 |
A♯ Diminished Inversions
| Position | Notes |
|---|---|
| Root Position | A♯ – C♯ – E |
| 1st Inversion | C♯ – E – A♯ |
| 2nd Inversion | E – A♯ – C♯ |
Key Signature
A Diminished 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.
How A♯ Diminished functions in a key
The same chord takes on a different harmonic role depending on the key it appears in. Here is where A♯ Diminished sits diatonically across the common keys:
- In B major, A♯ Diminished is the vii° chord — the dominant.
- In G♯ minor, A♯ Diminished is the ii° chord — a predominant.
A♯ Diminished — Frequently Asked Questions
What is the A♯ Diminished chord on piano?
The A♯ Diminished chord contains the notes A♯ – C♯ – E. On piano, play these notes together to sound the chord.
What notes are in the A# Diminished chord?
The A# Diminished chord contains: A# (root), C# (minor third), and E (diminished fifth). Both intervals are compressed: the minor third is 3 semitones above the root, and the diminished fifth is 6 semitones — a tritone.
How does A# Diminished differ from A# Minor?
A# Minor has a perfect fifth. A# Diminished lowers the fifth by one semitone to E (diminished fifth). That extra compression creates intense harmonic tension — the tritone between root and diminished fifth is the most dissonant interval in Western music.
What is the symbol for the A# Diminished?
A# Diminished is written as A#dim or A#°. The ° or "dim" symbol means both the third and fifth are minor/diminished. Do not confuse with A#dim7 or A#ø (half-diminished), which include additional notes.
What are the inversions of A# Diminished?
First inversion (A# Diminished/C#): C#–E–A#. Second inversion (A# Diminished/E): E–A#–C#. Diminished triads are used in classical music as the vii° chord — the chord one semitone below the tonic, with strong resolution pull.
How is A# Diminished used in music?
A# Diminished most commonly functions as the vii° chord in a major key, creating strong resolution back to the tonic. It also works as a chromatic passing chord between two nearby chords, and in classical music as a brief point of dissonance. Jazz uses the full four-note dim7 more often than the triad.
What songs use diminished chords?
Michelle (Beatles) uses a diminished chord as a chromatic passing chord. Many classical pieces use vii°–I cadences. Jazz standards use dim7 chords as chromatic passing and approach chords. Diminished harmony also appears in flamenco and film music for dramatic tension.