What notes are in C#m7b5?

C#m7b5 contains C# · E · G · B. Name any set of notes with the chord identifier.

What is the difference between half-diminished and fully diminished?

The seventh. Half-diminished uses a minor seventh; fully diminished lowers it again to a diminished seventh, which makes the chord symmetrical.

Where is a half-diminished chord used?

As the ii of a minor ii–V–i, and as the chord built on the seventh degree of a major scale.

What notes are in the C# Half-diminished chord?

The C# Half-diminished chord contains the notes C# · E · G · B: the root C# with the intervals 1P, 3m, 5d, 7m stacked above it. Play them together for the chord or one after another for an arpeggio. The lowest note is normally C#, but any chord tone can take the bass in an inversion.

What intervals make up the C# Half-diminished chord?

Measured from C#, the C# Half-diminished chord stacks the intervals 1P, 3m, 5d, 7m. The quality of the third and of the seventh, if there is one, is what gives the chord its character; the rest of the notes colour it. Every interval in the formula links to its own page, with its sound.

C# Half-Diminished Chord (C#m7b5): Notes, Piano & Guitar

Play it on your instrument

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Voicings on the piano

Voicing	Notes	Play it on your instrument
Closed, root position	C#3 · E3 · G3 · B3
Open (drop 2)	G2 · C#3 · E3 · B3
Shell	C#3 · E3 · B3
Rootless	E3 · G3 · B3 · C#4

Tap a key or a fret to hear it.

Anatomy

C# Half-diminished (C#m7b5) contains the notes C# · E · G · B, each with a role measured as an interval from the root.

Read on: how triads are built · seventh chords

Inversions

An inversion of C# Half-diminished puts a chord tone other than C# in the bass; the name after the slash is that bass note.

Where it lives

The keys and the scales C# Half-diminished belongs to.

In which keys

C# Half-diminished is diatonic to 3 keys; the numeral is its degree and the label its harmonic function.

D majorviiø7Dominant
B minoriiø7Subdominant
G# minorivø7Subdominant

Scales that contain it

C# Half-diminished fits inside these scales, each built on C#.

C# Minor BluesC# · E · F# · G · G# · B
C# LocrianC# · D · E · F# · G · A · B
C# Locrian PentatonicC# · E · F# · G · B
C# Super Locrian PentatonicC# · E · F · G · B
C# Locrian #2C# · D# · E · F# · G · A · B
C# Locrian 6C# · D · E · F# · G · A# · B
C# Bebop LocrianC# · D · E · F# · G · G# · A · B
C# Composite BluesC# · D# · E · E# · F# · G · G# · A# · B

Related chords

Chords that share most of their notes with C# Half-diminished: simpler and richer stacks of the same notes, and the substitutes a chart would accept.

Simpler

C#dimC# · E · G

Richer

C#m9b5C# · D# · E · G · B

Common substitutions

A9A · C# · E · G · B
C#m7b5 is A9 without its root.

Half-diminished on every root

Cm7b5 Dm7b5 D#m7b5 Em7b5 Fm7b5 F#m7b5 Gm7b5 G#m7b5 Am7b5 A#m7b5 Bbm7b5 Bm7b5

Open it in a tool

Understanding the C# Half-diminished chord

Names and symbols

C#m7b5 is the chord symbol for C# Half-diminished; it is also written C#ø, C#ø7, C#-7b5, C#h7, C#h.

The half-diminished seventh is written m7♭5 on charts and ø7 (or just ø) in jazz notation; both name the same four notes. It is not the diminished seventh, °7, whose seventh is a semitone lower.

How it is built

On C# it is C# · E · G · B, stacking 1P · 3m · 5d · 7m. It is written m7♭5 or with the ø symbol, and both mean the same thing: a diminished triad softened by a minor rather than a diminished seventh.

How it is used

It is the ii of a minor ii–V–i, which makes it one of the most frequently played chords in jazz despite sounding exotic in isolation. It is also the chord built on the seventh degree of a major scale.

Unlike the fully diminished seventh it is not symmetrical, so it has a clear home and a clear direction: down a fifth, to the dominant.

Learn this properly

Chapter 10: Chords: Triads and Sevenths

Common questions

What notes are in C#m7b5?: C#m7b5 contains C# · E · G · B. Name any set of notes with the chord identifier.
What is the difference between half-diminished and fully diminished?: The seventh. Half-diminished uses a minor seventh; fully diminished lowers it again to a diminished seventh, which makes the chord symmetrical.
Where is a half-diminished chord used?: As the ii of a minor ii–V–i, and as the chord built on the seventh degree of a major scale.
What notes are in the C# Half-diminished chord?: The C# Half-diminished chord contains the notes C# · E · G · B: the root C# with the intervals 1P, 3m, 5d, 7m stacked above it. Play them together for the chord or one after another for an arpeggio. The lowest note is normally C#, but any chord tone can take the bass in an inversion.
What intervals make up the C# Half-diminished chord?: Measured from C#, the C# Half-diminished chord stacks the intervals 1P, 3m, 5d, 7m. The quality of the third and of the seventh, if there is one, is what gives the chord its character; the rest of the notes colour it. Every interval in the formula links to its own page, with its sound.