C#m9b5

General info

Full name

C# Minor 9b5

Symbol

C#m9b5

Root

C#

Quality

Minor 9b5

Chord notes

Functions & resolutions

Stability / tension

Stable — can serve as major tonic

Most common resolutions

F#F# MajorG#G# MajorA#mA# Minor

Unstable degrees

4F#

b5G

resolves inward to the 4th

4F#

b7B

resolves down to the resolution tonic

Main resolution

C#m9b5source

G#G# Major

Major chord C# is a stable tonic. As tonic it doesn't require resolution, but in a progression context typically moves to IV or V.

Other resolutions

C#m9b5source

Deceptive resolution

A#mA# Minor

As the V degree, a major chord can defy expectations by moving to vi instead of I (deceptive cadence).

C#m9b5source

Modal resolution

BB Major

In modal context, a major chord can freely move to bVII, bIII, or bVI — characteristic of Mixolydian mode.

C#m9b5source

Jazz reharmonization

C#maj7C# Major 7

In jazz, a major chord is enriched to maj7, 6/9, or add9 and can smoothly transition into a ii-V of another key (modulation).

C#m9b5source

Functional resolution

G#G# Major

As the IV degree (subdominant), a major chord can resolve to V or directly to I (plagal cadence).

Features

Character

Half-diminished, with an added 9th

Characteristic interval

Diminished 5th (b5), 9th

Description

The minor 3rd, diminished 5th, and minor 7th form a half-diminished seventh chord; the major 9th adds a diatonic extension. The b5 dissonance preserves the instability of the core.

Application

• ii-V in minor (extended)
• Modern jazz
• Substitute for m7b5 with ninth

Voicing & structure

Harmony

Compatible scales

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