A Half-Diminished Seventh (Minor 7♭5)
Chord Tones: A Half-Diminished Seventh (Minor 7♭5)
Symbol: ø7, m7♭5 — 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 | G | 391.995 Hz |
Chord Notation
| Notation Type | Symbol / Value |
|---|---|
| Lead Sheet Symbol | Aø7 |
| All Common Symbols | ø7, m7♭5 |
| Interval Formula | 1-♭3-♭5-♭7 |
| Harmonic Category | dissonant |
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# – G | A | A Half-Diminished Seventh (Minor 7♭5) |
| First Inversion | C – D# – G – A | C | A Half-Diminished Seventh (Minor 7♭5)/C |
| Second Inversion | D# – G – A – C | D# | A Half-Diminished Seventh (Minor 7♭5)/D# |
| Third Inversion | G – A – C – D# | G | A Half-Diminished Seventh (Minor 7♭5)/G |
Harmonic Function
The A half diminished 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 stable harmonic grounding.
The half-diminished chord (minor seven flat five) combines a diminished triad with a minor seventh. It is the ii chord in minor keys and an essential sound in jazz and classical harmony.
Common Progressions
The A Half-Diminished Seventh (Minor 7♭5) frequently appears in these progression patterns (shown in Roman numeral notation relative to key):
iiø-V7-iviiø-I
Songs Featuring the Half-Diminished Seventh (Minor 7♭5)
Well-known songs where the A Half-Diminished Seventh (Minor 7♭5) — or this chord type — plays a prominent role:
- Autumn Leaves (minor ii chord) – jazz standard
- Beautiful Love – jazz standard
- Solar – Miles Davis
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 |
| G | 391.995 Hz | 391.111 Hz | 392.438 Hz |
Scales Containing the A Half-Diminished Seventh (Minor 7♭5)
These scales include the A Half-Diminished Seventh (Minor 7♭5) as a diatonic or characteristic chord: