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Learn the C Half-Diminished 7th Chord on PianoCm7b5Half-Diminished 7th

Minor with flat 5

Chord Information

Learn how to play Cm7b5 on piano

Notes in Chord

C
Eb
Gb
Bb

Intervals

1
m3
d5
m7

Inversion

Notes (bottom to top): C4 - Eb4 - Gb4 - Bb4

Right Hand Fingering

Fingers: 1-2-3-5
1=thumb, 2=index
3=middle, 4=ring, 5=pinky

Interactive Piano

Click the highlighted keys to play the Cm7b5 chord

Click any key to load sounds
C
D
E
F
G
A
B
C#
D#
F#
G#
A#

About the Cm7b5 Chord

The Cm7b5 chord (also written Cø7) occupies a unique harmonic space—darker than minor seventh but less extreme than fully diminished. Built from C-Eb-Gb-Bb, this half-diminished seventh chord is essential in minor key harmony, typically functioning as the ii chord in minor keys.

What makes Cm7b5 special is its pivotal role in minor ii-V-i progressions. In Bb minor, Cm7b5 is the ii chord, leading to F7 and then Bbm. This progression drives countless jazz standards with minor themes. The "half" in half-diminished refers to its seventh being minor (Bb) rather than diminished.

On piano, Cm7b5 combines C and Bb (white) with Eb and Gb (black). The chord's dark color and unstable quality create forward motion that resolves beautifully to dominant chords.

Music Theory & Usage

Cm7b5 functions primarily as ii in Bb minor, where it leads the ii-V-i progression (Cm7b5-F7-Bbm). This is one of jazz's most important minor-key cadences. The chord also appears as vii in Db major.

The half-diminished sound is essential in jazz standards with minor themes and in any music requiring sophisticated minor harmony.

Famous Songs Using Cm7b5

Hear how professional musicians use the Cm7b5 chord in these well-known songs:

Autumn Leaves

by Joseph Kosma

Uses m7b5 chords in its minor ii-V-i progressions

Stella by Starlight

by Victor Young

Features half-diminished chords throughout

Beautiful Love

by Victor Young

Contains m7b5 in its minor key harmony

Softly, As in a Morning Sunrise

by Sigmund Romberg

Uses half-diminished for minor ii-V-i

How to Play Cm7b5 on Piano

  1. Place your thumb on C.
  2. Place your index finger on Eb.
  3. Place your middle finger on Gb.
  4. Place your pinky finger on Bb.
  5. Press all keys simultaneously to hear the Cm7b5 chord.

Recommended fingering: 1-2-3-5 (right hand)

Cm7b5 Chord Inversions

The Cm7b5 chord can be played in different inversions:

Root Position

C - Eb - Gb - Bb (bass note: C)

First Inversion

Eb - Gb - Bb - C (bass note: Eb)

Second Inversion

Gb - Bb - C - Eb (bass note: Gb)

Common Chord Progressions Using Cm7b5

ii-V-I Jazz Progression

Common chord progression

Dm7Cm7b5Gmaj7

I-vi-ii-V Progression

Common chord progression

Gmaj7Em7Dm7Cm7b5

Practice Tips for Cm7b5

  • Start slowly and focus on pressing all keys simultaneously for a clean sound.
  • Practice transitioning between Cm7b5 and other common chords to build muscle memory.
  • Listen carefully to how the seventh interval creates tension and color in the chord.
  • Practice resolving this chord to its natural target chords in progressions.

Frequently Asked Questions about Cm7b5

What notes are in Cm7b5?

Cm7b5 contains C (root), Eb (minor 3rd), Gb (diminished 5th), and Bb (minor 7th). The "b5" indicates the diminished fifth; the "7" is a minor seventh.

What's the difference between Cm7b5 and Cdim7?

Cm7b5 (C-Eb-Gb-Bb) has a minor 7th—darker but not fully diminished. Cdim7 (C-Eb-Gb-Bbb/A) has a diminished 7th—fully symmetrical and more tense. Cm7b5 is "half" diminished; Cdim7 is fully diminished.

Why is Cm7b5 written with "ø"?

The ø symbol (slashed circle) is shorthand for half-diminished. It's faster to write than "m7b5" and distinguishes it from fully diminished (°). Both notations mean the same thing.

How is Cm7b5 used in minor keys?

Cm7b5 is the ii chord in Bb minor. It leads to F7 (V7) which resolves to Bbm (i). This ii-V-i in minor is essential in jazz and creates sophisticated minor-key cadences.

Quick Reference

Root NoteC
QualityhalfDiminished7
NotesC-Eb-Gb-Bb
Fingering1-2-3-5
Categoryseventh

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