C#7b9#5

General info

Full name

C# 7b9#5

Symbol

C#7b9#5

Root

C#

Quality

7b9#5

Chord notes

Functions & resolutions

Typical function in key

vii°Leading tone (vii°)D major

Stability / tension

Stable — can serve as major tonic

Most common resolutions

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

Unstable degrees

#5A

6A#

resolves up to the 6th

4F#

b7B

resolves down to the resolution tonic

Main resolution

C#7b9#5source

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#7b9#5source

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#7b9#5source

Modal resolution

BB Major

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

C#7b9#5source

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#7b9#5source

Functional resolution

G#G# Major

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

Substitutions

Tritone substitution

G7G Dominant 7

Features

Character

Dominant, with b9 and #5

Characteristic interval

Augmented 5th (#5), Minor 9th (b9)

Description

The augmented 5th and minor 9th alter two tones of a dominant seventh chord. Both allow semitone voice leading into the next chord, giving the sonority sharp, directed tension.

Application

• Jazz cadences V → i
• Altered dominant
• Harmonic minor

Voicing & structure

Harmony

Compatible scales

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