The D-sharp dominant seventh flat five chord (abbreviated "D#7(b5) chord") is a four-note chord consisting of the notes D♯, F, A, and C♯. The chord is formed by lowering the fifth of a D-sharp dominant seventh chord a half step.
D-sharp dominant seventh flat five chord
D♯ F A C♯
1 3 ♭5 ♭7
tetrad (four-note chord)