B#9 chord
The B-sharp dominant ninth chord (abbreviated "B#9 chord") is a five-note chord consisting of the notes B♯, D, F, A♯, and C. The chord is formed by adding a major ninth to a B-sharp dominant seventh chord.
In practice, the fifth (F) is sometimes omitted from the B#9 chord because it's not always possible to play all notes simultaneously.
Name
B-sharp dominant ninth chord
Notes
B♯ D F A♯ C
Intervals
1 3 5 ♭7 9
Chord symbol
B♯9
Type
Pentad (five-note chord)