The C#m7b5 chord (C sharp minor 7 flat 5, or C sharp half diminished) contains the notes C#, E, G and B, which is the 1 (root) b3, b5 and b7 of the C# Major scale. It can be viewed as a C#m7 chord with a flat 5 or a C# diminished chord with an added b7.

The half diminished chord can sound like a very dissonant chord, when played in isolation. However, when played in the context of other chords, it can sound beautiful. C#m7b5 is the 7th chord in the key of D Major. Try playing a D chord, then a C#m7b5 chord and then return to D. This is an example of how C#m7b5 can sound beautiful in context.

The C#m7b5 chord is most commonly played with the root note on the 4th fret of the 5th string (2nd shape down, in the picture below).

10 Ways To Play The C#m7b5 Chord

If you’ve come to this page just to view some chord diagrams for C#m7b5 (C sharp half diminished), here they are.

C#m7b5 Chord 10 Shapes

Some Quick C#m7b5 Chord Theory

  • The C sharp minor 7 flat 5 chord contains the notes C#, E, G and B.
  • The C#m7b5 chord is produced by playing the 1st (root), flat 3rd, flat 5th and flat 7th of the C# Major scale.
  • The C sharp minor 7 flat 5 chord (just like all half diminished chords) contains the following intervals (from the root note): minor 3rd, minor 3rd, Major 3rd, Major 2nd (back to the root note).
  • C#m7b5 is a C# diminished chord, with an added flat 7th (B) included, or a C#m7 chord with the 5th lowered by a semitone.
  • C#m7b5 is the 7th chord in the key of D.
  • The C# locrian mode can be used when soloing over the C#m7b5 chord.

Further Reading