The D♯ Dominant 9th chord is a five-note chord made up of D♯, F♯♯, A♯, C♯, and E♯. It is built from a root, major third, perfect fifth, minor seventh, and major ninth.
Construction
D♯ Dominant 9th = Root + Major 3rd + Perfect 5th + Minor 7th + Major 2nd = D♯ · F♯♯ · A♯ · C♯ · E♯
| Note | Interval | Degree |
|---|---|---|
| D♯ | Root | 1 |
| F♯♯ | Major 3rd | 3 |
| A♯ | Perfect 5th | 5 |
| C♯ | Minor 7th | ♭7 |
| E♯ | Major 2nd | 9 |
Key Signature
A dominant chord points home to the key a fifth below its root: the D♯ Dominant 9th is the V (dominant) of G# Major, so the relevant key signature is that key’s — 4 flats (B♭, E♭, A♭, D♭). Spelled as a scale, these notes are D# Mixolydian.
B♭E♭A♭D♭
Order of flats
Flats are added in a fixed order — the reverse of the sharp order. Each new flat key adds the next flat on the list.
B♭E♭A♭D♭G♭C♭F♭
Mnemonic: Battle Ends And Down Goes Charles’ Father
Chords in the Key of G♯ Major
These are the triads built on each degree of the G♯ major scale:
D♯ Dominant 9th — Frequently Asked Questions
What is the D♯ Dominant 9th chord on piano?
The D♯ Dominant 9th chord contains the notes D♯ – F♯♯ – A♯ – C♯ – E♯. On piano, play these notes together to sound the chord.
What notes are in the D# Dominant 9th chord?
The D# Dominant 9th chord (D#9) contains 5 notes: D#, G, A#, C#, F. Formula: R-M3-P5-m7-M9.
How is D#9 used in music?
D#9 is used in jazz, fusion, and contemporary music to add harmonic color. It appears as a dominant or tonic chord depending on context.
What is the scale degree formula for D#9?
D#9 uses scale degrees 1-3-5-b7-9, giving it its distinctive sound.