Chords in F# Mixolydian
F# Mixolydian is built from the notes F#, G#, A#, B, C#, D# and E. Its scale carries 5 sharps. Harmonising that scale in thirds gives seven chords — 3 majors, 3 minors and 1 diminished — starting on F# as the I. The chord on the fifth degree is C#m rather than a major V, so F# Mixolydian has no leading tone and resolves by step and colour instead of by dominant pull — the sound that separates it from a plain F# minor.
Beyond those seven, F# Mixolydian commonly borrows F#m (i), G#dim (iiø), A (bIII), Bm (iv) and D (bVI) from the parallel minor — the mixture chords that give a progression somewhere unexpected to go.
The seven chords
Extended to four notes each, the same seven degrees give F#7, G#m7, A#m7b5, Bmaj7, C#m7, D#m7, Emaj7.
Borrowed chords
Capo 4 and play D Mixolydian shapes to sound F# Mixolydian.
All eight capo positions for F# Mixolydian →