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