C#m7b5

General info

Full name

C# Half-dim 7

Symbol

C#m7b5

Root

C#

Quality

Half-dim 7

Chord notes

Functions & resolutions

Typical function in key

vii°Leading tone (vii°)D major

Stability / tension

High tension — pulls toward the dominant

Most common resolutions

F#7F# Dominant 7BmB Minor

Unstable degrees

2D#

b3E

resolves down to the 2nd

4F#

b5G

resolves inward to the 4th

4F#

b7B

resolves down to the resolution tonic

Main resolution

C#m7b5source

F#7F# Dominant 7

Half-diminished C#m7b5 typically acts as ii in minor, resolving to the dominant (F#7), which then leads to the tonic.

Other resolutions

C#m7b5source

Deceptive resolution

BmB Minor

The half-diminished chord can bypass the dominant and resolve directly to the minor tonic — a plagal turn in minor.

C#m7b5source

No resolution needed

In the Locrian mode, a half-diminished chord can function as the tonic, requiring no resolution.

C#m7b5source

Jazz reharmonization

Em6E Minor 6

In jazz, ø7 is common in ii-V-i progressions but can be substituted with iv6, sharing the same notes.

C#m7b5source

Functional resolution

AA Major

Besides moving to the dominant, the half-diminished chord can resolve to bVI — creating a Phrygian color.

Features

Character

Half-diminished, unstable

Characteristic interval

Diminished 5th (b5)

Description

The diminished fifth creates instability, the minor seventh softens it. Less tense than fully diminished.

Application

• iiø7 in natural minor
• Jazz ii–V in minor
• Unstable predominant sonorities

Voicing & structure

Harmony

Harmonic context

viim7b5D majorDominantiim7b5B minorPredominantvim7b5E DorianToniciiim7b5A MixolydianTonic

Compatible scales

All chord tones are contained in these scales — use them for improvisation.