What notes are in a C♯ diminished 7 chord?

C♯°7 contains four notes: C♯ (root), E (minor third), G (diminished fifth), and B♭ (diminished seventh).

How does C♯°7 resolve?

In D minor: C♯ rises to D, E holds or falls to D, G falls to F, and B♭ falls to A — every voice moves by half-step or whole-step to a chord tone of D minor.

Why are dim7 chords symmetric?

Every interval is a minor third (3 semitones). 3+3+3+3 = 12 semitones = an octave. So C♯°7, E°7, G°7, and B♭°7 all contain the same four pitches in different inversions.

Where does C♯°7 appear in famous music?

Bach's Toccata and Fugue in D Minor uses it constantly. Mozart's K. 397 Fantasia in D minor opens with parallel diminished sonorities. Beethoven's "Pathétique" Sonata Op. 13 opens with C°7 → resolution.

C# diminished 7 chord — notes, intervals, and practice

C♯°7 — C♯, E, G, B♭ — is the vii°7 chord of D minor (and enharmonically the vii°7 of D major when the leading-tone harmony borrows from the parallel minor). The chord stacks three minor thirds, producing a fully symmetric four-note structure; rotating any note to the bass yields E°7, G°7, or B♭°7 — all the same four pitches.

Intervals

The C# diminished 7 chord stacks two thirds on the root. Each interval and its size in semitones:

C#→Eminor 3rd3 semitones
E→Gminor 3rd3 semitones
G→Bbdiminished 7th9 semitones

On the keyboard

Each note of the C# diminished 7 chord highlighted on a piano. Pitch class is what matters — any octave works.

On the guitar

One voicing of the C# diminished 7 chord on a six-string guitar fretboard.

Common mistakes

The seventh is B♭ (a diminished 7th from C♯, enharmonic to A♯). Replacing it with B natural makes a half-diminished chord (C♯m7♭5); the diminished 7th distinction is the lowered B♭. Bach uses C♯°7 constantly in his D-minor literature — the Toccata and Fugue is full of these chords as cadential preparations.

In context

C♯°7 → D minor is the strongest cadence in D minor — every voice resolves by half-step or whole-step to the tonic chord. C♯°7 also substitutes for A7♭9 as an altered dominant (omit the A and you have C♯°7). Liszt uses dim7 chords as modulation pivots throughout his Hungarian Rhapsodies.

Drill it

The C# diminished 7 chord is one of 48 in the Chord Trainer. Open the full trainer to practice it alongside related chords with timing and best-time tracking.

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Frequently asked

What notes are in a C♯ diminished 7 chord?: C♯°7 contains four notes: C♯ (root), E (minor third), G (diminished fifth), and B♭ (diminished seventh).
How does C♯°7 resolve?: In D minor: C♯ rises to D, E holds or falls to D, G falls to F, and B♭ falls to A — every voice moves by half-step or whole-step to a chord tone of D minor.
Why are dim7 chords symmetric?: Every interval is a minor third (3 semitones). 3+3+3+3 = 12 semitones = an octave. So C♯°7, E°7, G°7, and B♭°7 all contain the same four pitches in different inversions.
Where does C♯°7 appear in famous music?: Bach's Toccata and Fugue in D Minor uses it constantly. Mozart's K. 397 Fantasia in D minor opens with parallel diminished sonorities. Beethoven's "Pathétique" Sonata Op. 13 opens with C°7 → resolution.