C Half-Diminished Seventh (Minor 7♭5)

Chord Tones: C Half-Diminished Seventh (Minor 7♭5)

Symbol: ø7, m7♭5 — Formula: 1-♭3-♭5-♭7

DegreeNoteFrequency (A=440, Equal)
1 C 261.626 Hz
♭3 D# 311.127 Hz
♭5 F# 369.994 Hz
♭7 A# 466.164 Hz

Chord Notation

Notation TypeSymbol / Value
Lead Sheet SymbolCø7
All Common Symbolsø7, m7♭5
Interval Formula1-♭3-♭5-♭7
Harmonic Categorydissonant

Roman numeral (e.g. I, IV, V) and Nashville Number notation are key-dependent. See Keys pages for chord function within specific keys.

Inversions

InversionNotes (low to high)Bass NoteSlash Notation
Root Position C D# F# A# C C Half-Diminished Seventh (Minor 7♭5)
First Inversion D# F# A# C D# C Half-Diminished Seventh (Minor 7♭5)/D#
Second Inversion F# A# C D# F# C Half-Diminished Seventh (Minor 7♭5)/F#
Third Inversion A# C D# F# A# C Half-Diminished Seventh (Minor 7♭5)/A#

Harmonic Function

The C half diminished chord commonly functions as the tonic (I) in C major/minor. Its harmonic role varies by key — in major keys it provides stable harmonic grounding.

The half-diminished chord (minor seven flat five) combines a diminished triad with a minor seventh. It is the ii chord in minor keys and an essential sound in jazz and classical harmony.

Common Progressions

The C Half-Diminished Seventh (Minor 7♭5) frequently appears in these progression patterns (shown in Roman numeral notation relative to key):

Songs Featuring the Half-Diminished Seventh (Minor 7♭5)

Well-known songs where the C Half-Diminished Seventh (Minor 7♭5) — or this chord type — plays a prominent role:

Tuning Frequencies Across Temperaments

Frequencies shown at A=440 Hz. View full temperament data for any note.

NoteEqual Temp.PythagoreanJust Intonation
C 261.626 Hz 260.740 Hz 261.626 Hz
D# 311.127 Hz 309.026 Hz 313.951 Hz
F# 369.994 Hz 371.251 Hz 367.911 Hz
A# 466.164 Hz 463.538 Hz 470.926 Hz

Scales Containing the C Half-Diminished Seventh (Minor 7♭5)

These scales include the C Half-Diminished Seventh (Minor 7♭5) as a diatonic or characteristic chord: