A seventh flat nine chord is created by adding a flattened 9th degree to any dominant 7th chord. For example, a C7b9 chord contains the notes C, E, G, Bb and Db (1, 3, 5, b7 and b9). Here are some common open seventh flat 9 chord shapes.
C7b9
Db7b9
D7b9
Eb7b9
E7b9
F7b9
F#7b9
G7b9
A7b9
A7b9
Bb7b9
B7b9