C Sixth-Ninth Chord
Chord Tones: C Sixth-Ninth Chord
Symbol: 6/9 — Formula: 1-3-5-6-9
| Degree | Note | Frequency (A=440, Equal) |
|---|---|---|
| 1 | C | 261.626 Hz |
| 3 | E | 329.628 Hz |
| 5 | G | 391.995 Hz |
| 6 | A | 440.000 Hz |
| 9 | D | 293.665 Hz |
Chord Notation
| Notation Type | Symbol / Value |
|---|---|
| Lead Sheet Symbol | C6/9 |
| All Common Symbols | 6/9 |
| Interval Formula | 1-3-5-6-9 |
| Harmonic Category | bright |
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 | C – E – G – A – D | C | C Sixth-Ninth Chord |
| First Inversion | E – G – A – D – C | E | C Sixth-Ninth Chord/E |
| Second Inversion | G – A – D – C – E | G | C Sixth-Ninth Chord/G |
| Third Inversion | A – D – C – E – G | A | C Sixth-Ninth Chord/A |
| Fourth Inversion | D – C – E – G – A | D | C Sixth-Ninth Chord/D |
Harmonic Function
The C sixth ninth chord commonly functions as the tonic (I) in C major/minor. Its harmonic role varies by key — in major keys it provides stable harmonic grounding.
The 6/9 chord adds both the sixth and ninth to a major triad without a seventh. It has a rich, colorful sound with a jazz and bossa nova flavor, often used as a final tonic chord.
Common Progressions
The C Sixth-Ninth Chord frequently appears in these progression patterns (shown in Roman numeral notation relative to key):
I6/9-IVmaj7
Songs Featuring the Sixth-Ninth Chord
Well-known songs where the C Sixth-Ninth Chord — or this chord type — plays a prominent role:
- Chameleon – Herbie Hancock
- Mercy Mercy Mercy – Cannonball Adderley
- Four – 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 |
|---|---|---|---|
| C | 261.626 Hz | 260.740 Hz | 261.626 Hz |
| E | 329.628 Hz | 330.001 Hz | 327.032 Hz |
| G | 391.995 Hz | 391.111 Hz | 392.438 Hz |
| A | 440.000 Hz | 440.000 Hz | 436.043 Hz |
| D | 293.665 Hz | 293.332 Hz | 294.329 Hz |
Scales Containing the C Sixth-Ninth Chord
These scales include the C Sixth-Ninth Chord as a diatonic or characteristic chord: