C Half Diminished

Notes:C – Eb – Gb – Bb
Formula:R-m3-d5-m7
Intervals:P1-m3-d5-m7
Scale Degrees:1-b3-b5-b7

Introduction

The C Half Diminished piano chord (Cm7b5) consists of the notes C, Eb, Gb, Bb. It is a diminished triad with an added minor 7th, giving it a dark, moody, and tense character commonly used in jazz and minor key progressions. Formula: R-m3-d5-m7 | Scale degrees: 1-b3-b5-b7.

Notes

Notes:C – Eb – Gb – Bb

C Half Diminished Inversions

PositionNotes
Root PositionC4 – Eb4 – Gb4 – Bb4
1st InversionEb4 – Gb4 – Bb4 – C5
2nd InversionGb4 – Bb4 – C5 – Eb5
3rd InversionC4 – Eb4 – Gb4 – Bb3

Key Signature

The key of C Half Diminished has No sharps or flats.

Theory: Intervals

Formula: R-m3-d5-m7
Intervals: P1-m3-d5-m7

The C Half Diminished is built by stacking intervals from the root note. The formula R-m3-d5-m7 describes the scale degrees used. The intervals P1-m3-d5-m7 show the distance between each note in the chord.

C Half Diminished β€” Frequently Asked Questions

What notes are in the C Half Diminished chord?

Cm7b5 contains four notes: C (root), Eb (minor third), Gb (diminished fifth), and Bb (minor seventh). A diminished triad with a minor seventh β€” dark, moody, and tense.

How does Cm7b5 differ from Cdim7?

Cm7b5 has Bb (minor seventh). Cdim7 has A (diminished seventh). Half-diminished is less tense than fully diminished β€” the minor seventh softens it slightly.

How does Cm7b5 differ from Cm7?

Cm7b5 has Gb (diminished fifth). Cm7 has G (perfect fifth). The flatted fifth adds significant tension and darkness.

How is Cm7b5 used in music?

Cm7b5 is the ii chord in Bb minor jazz harmony (Cm7b5–F7–Bbm). It is essential for minor-key ii–V–i progressions. Also the vii chord in Db Major.

What songs use Half Diminished chords?

Half-diminished chords are essential in jazz minor-key harmony. Autumn Leaves uses the iiΒ°7–V7–i in G minor. Still Crazy After All These Years (Paul Simon) features half-diminished harmony.

Is Cm7b5 the same as Ebm6?

Same four notes (C, Eb, Gb, Bb = Eb, Gb, Bb, C). Context determines the name: Cm7b5 when C is root, Ebm6 when Eb is root.

Practice Tips

  • The minor-key ii–V–i: Cm7b5 β†’ F7 β†’ Bbm is essential jazz vocabulary.
  • Compare Cm7b5 with Cdim7 β€” minor seventh vs diminished seventh.
  • Compare Cm7b5 with Cm7 β€” one note (Gb vs G) transforms smooth into tense.
  • Cm7b5 and Ebm6 are the same notes β€” context determines the name.
  • Half-diminished is the sound of minor-key jazz β€” learn it in all keys.
  • The symbol ΓΈ (slash through the circle) means half-diminished.