A Diminished Seventh Chord
Chord Tones: A Diminished Seventh Chord
Symbol: dim7, °7 — Formula: 1-♭3-♭5-𝄫7
| Degree | Note | Frequency (A=440, Equal) |
|---|---|---|
| 1 | A | 440.000 Hz |
| ♭3 | C | 261.626 Hz |
| ♭5 | D# | 311.127 Hz |
| 𝄫7 | F# | 369.994 Hz |
Chord Notation
| Notation Type | Symbol / Value |
|---|---|
| Lead Sheet Symbol | Adim7 |
| All Common Symbols | dim7, °7 |
| Interval Formula | 1-♭3-♭5-𝄫7 |
| Harmonic Category | tense |
Roman numeral (e.g. I, IV, V) and Nashville Number notation are key-dependent. See Keys pages for chord function within specific keys.
Inversions
| Inversion | Notes (low to high) | Bass Note | Slash Notation |
|---|---|---|---|
| Root Position | A – C – D# – F# | A | A Diminished Seventh Chord |
| First Inversion | C – D# – F# – A | C | A Diminished Seventh Chord/C |
| Second Inversion | D# – F# – A – C | D# | A Diminished Seventh Chord/D# |
| Third Inversion | F# – A – C – D# | F# | A Diminished Seventh Chord/F# |
Harmonic Function
The A diminished seventh chord commonly functions as the submediant (vi) in C major or dominant (V) in D major. Its harmonic role varies by key — in major keys it provides extended harmonic tension.
The diminished seventh chord consists of four equally-spaced minor thirds, creating a symmetrical, highly dissonant chord. It is used as a dramatic pivot chord and in chromatic passing harmony.
Common Progressions
The A Diminished Seventh Chord frequently appears in these progression patterns (shown in Roman numeral notation relative to key):
vii°7-I#iv°7-V
Songs Featuring the Diminished Seventh Chord
Well-known songs where the A Diminished Seventh Chord — or this chord type — plays a prominent role:
- While My Guitar Gently Weeps – Beatles
- Georgia on My Mind – Ray Charles
- Sophisticated Lady – Duke Ellington
Tuning Frequencies Across Temperaments
Frequencies shown at A=440 Hz. View full temperament data for any note.
| Note | Equal Temp. | Pythagorean | Just Intonation |
|---|---|---|---|
| A | 440.000 Hz | 440.000 Hz | 436.043 Hz |
| C | 261.626 Hz | 260.740 Hz | 261.626 Hz |
| D# | 311.127 Hz | 309.026 Hz | 313.951 Hz |
| F# | 369.994 Hz | 371.251 Hz | 367.911 Hz |
Scales Containing the A Diminished Seventh Chord
These scales include the A Diminished Seventh Chord as a diatonic or characteristic chord: