C#/D♭ 9th chords Author: Juan Martinez Categories: C♯ Chords Tags: 9th chords C#9 chord on a piano Formula: 1-3-5-♭7-9 Notes: C#-E#-G#-B-D# chord suffix: C#9 Use these charts to create your own C#9 chord or play a C#9 melody. C#9 chord on a pianoC# 9th chord on a guitar