Bbm7b5

General info

Full name

Bb Half-dim 7

Symbol

Bbm7b5

Root

Bb

Quality

Half-dim 7

Chord notes

Functions & resolutions

Typical function in key

viRelative tonic (vi)C# major

Stability / tension

High tension — pulls toward the dominant

Most common resolutions

Eb7Eb Dominant 7AbmAb Minor

Unstable degrees

2C

b3Db

resolves down to the 2nd

4Eb

b5E

resolves inward to the 4th

4Eb

b7Ab

resolves down to the resolution tonic

Main resolution

Bbm7b5source

Eb7Eb Dominant 7

Half-diminished Bbm7b5 typically acts as ii in minor, resolving to the dominant (Eb7), which then leads to the tonic.

Other resolutions

Bbm7b5source

Deceptive resolution

AbmAb Minor

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

Bbm7b5source

No resolution needed

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

Bbm7b5source

Jazz reharmonization

Dbm6Db Minor 6

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

Bbm7b5source

Functional resolution

GbGb 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

viim7b5B majorDominantvim7b5C# DorianToniciiim7b5F# MixolydianTonic

Compatible scales

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