C#9 piano chord — the keys, the inversions, the theory
C#9 is a ninth chord built from C#, E#, G#, B, D#. Below: the keys to press, every inversion with its own diagram, the intervals it is made of, the keys whose scale contains it, and a progression that actually uses it. Press any diagram to hear it.
C#9
C# · E# · G# · B · D#
Semitones above the root: 0 – 4 – 7 – 10 – 14
A major third with a flattened seventh above it: unstable on purpose, and it wants to resolve a fourth up.
Inversions of C#9
Root position
C# · E# · G# · B · D# · bass C#
Inversion 1
E# · G# · B · C# · D# · bass E#
Inversion 2
G# · B · C# · D# · E# · bass G#
Inversion 3
B · C# · D# · E# · G# · bass B
Same chord, different note at the bottom. Press a diagram to hear it — inversions are how you move between chords without jumping your hand across the keyboard.
Keys that contain C#9
- F#V
In F# it does this job: I – V – vi – IV
- F#
- C#9
- D#m
- B