C Dominant Ninth Chord

Chord Tones: C Dominant Ninth Chord

Symbol: 9 — Formula: 1-3-5-♭7-9

Chord Notation

Roman numeral (e.g. I, IV, V) and Nashville Number notation are key-dependent. See Keys pages for chord function within specific keys.

Inversions

Harmonic Function

The C dominant 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 dominant ninth chord extends the dominant seventh with a ninth, adding color and richness to one of music's most harmonically active chords. Essential in jazz, blues, and funk. The C Dominant Ninth Chord specifically contains 5 notes: C, E, G, A♯, D (formula: 1-3-5-♭7-9). On piano, C-rooted chords sit entirely on white keys in their basic triad form, making them the first chords most students learn. Pop, folk, and singer-songwriter music heavily use C-rooted chords because open-position guitar voicings and piano shapes are immediately accessible.

Common Progressions

The C Dominant Ninth Chord frequently appears in these progression patterns (shown in Roman numeral notation relative to key):

• V9-I
• ii7-V9-I

Songs Featuring the Dominant Ninth Chord

Well-known songs where the C Dominant Ninth Chord — or this chord type — plays a prominent role:

• Purple Haze – Jimi Hendrix
• What's Going On – Marvin Gaye
• Superstition – Stevie Wonder

Tuning Frequencies Across Temperaments

Frequencies shown at A=440 Hz. View full temperament data for any note.

Scales Containing the C Dominant Ninth Chord

These scales include the C Dominant Ninth Chord as a diatonic or characteristic chord: