C♯m7♭5
C# Half-Diminished — the half-diminished — a minor seventh with a flattened fifth, the classic ii chord in minor keys.
The keys
C♯ – E – G – B
What's inside C♯m7♭5
| Note | Interval from root | Degree |
|---|---|---|
| C♯ | Root | 1 |
| E | Minor 3rd | b3 |
| G | Diminished 5th | b5 |
| B | Minor 7th | b7 |
Inversions
| Position | Keys (low → high) |
|---|---|
| Root position | D♭4 – E4 – G4 – B4 |
| 1st inversion | E4 – G4 – B4 – D♭5 |
| 2nd inversion | G4 – B4 – D♭5 – E5 |
| 3rd inversion | B4 – D♭5 – E5 – G5 |
A working voicing
Split the chord between two hands the way working players do — a solid shell low down, the colour tones up top:
| Hand | Keys |
|---|---|
| Left (shell) | D♭2 – B2 |
| Right (colour) | E4 – G4 |
Where C♯m7♭5 lives
As the ii chord
C♯m7♭5 → G♭7 → Bmaj7
Minor-family sevenths live on the ii — this is the move they were born for.
Stepwise colour
D♭ → C♯m7♭5 → E♭m7
Used as a passing colour between neighbouring chords.
Put C♯m7♭5 under your fingers
Hear every voicing, see the keys light up, and drill it in the interactive Chord & Voicing Lab.
Open the Chord & Voicing Lab →