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Note identifier · Reference entry

What chord is C–E♭–F♯?

The notes C, E♭, and F♯ spell C Diminished (Cdim) — C the root, E♭ the ♭3, and G♭ the ♭5.

Ranked readings

Every chord these notes can spell, most complete first. The bass note anchors the root-position reading; each candidate maps every note to its scale degree.

C DiminishedCdimConfident

Every tone of Cdim is present, with C in the bass — the definitive reading.

DegreeNoteIn this set
1Csounding
♭3E♭sounding
♭5G♭sounding
E♭ Minor 6thE♭m6Likely

root, ♭3, and 6th of E♭m6 sound; it reads as E♭m6 with the B♭ (5) omitted.

DegreeNoteIn this set
1E♭sounding
♭3G♭sounding
5B♭omitted
6Csounding
D 7♭9D7♭9Partial

3rd, ♭7, and ♭9 of D7♭9 sound; it reads as D7♭9 with the D (1) and A (5) omitted.

DegreeNoteIn this set
1Domitted
3F♯sounding
5Aomitted
♭7Csounding
♭9E♭sounding

Not these chords

Names these notes are often mistaken for. Each is ruled out because a defining tone of that chord is missing — the note that would make the name true simply is not being played.

Not Cdim7

Not Cdim7: a diminished 7th C chord needs B♭♭ as its ♭♭7 — B♭♭ is absent.

Not E♭dim7

Not E♭dim7: a diminished 7th E♭ chord needs B♭♭ as its ♭5 — B♭♭ is absent.

Not F♯dim7

Not F♯dim7: a diminished 7th F♯ chord needs A as its ♭3 — A is absent.

Not Cm7♭5

Not Cm7♭5: a half diminished C chord needs B♭ as its ♭7 — B♭ is absent.

Not Cdim(maj7)

Not Cdim(maj7): a diminished major 7th C chord needs B as its 7th — B is absent.

How these notes relate

C, E♭, and F♯ is a voicing of E♭m6 with the B♭ (5th) left out.

Add B♭♭ (its ♭♭7) and the set reads as Cdim7.

Set-class analysis

The pitch-class set theory identity of these notes — order- and key-independent, computed from the set itself.

Pitch-class set
{0, 3, 6}
Normal order
[0,3,6]
Prime form
[0,3,6]
Interval vector
<002001>
Forte set class
3-10

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