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Chord · Reference entry
C mi11♭5
mi11♭5 · C – E♭ – G♭ – B♭ – D – F · intervals P1-m3-d5-m7-M9-P11
The C mi11♭5 chord (Cm11♭5) contains the notes C, E♭, G♭, B♭, D, and F. Its interval formula is R-m3-d5-m7-M9-P11. A minor 11th with a lowered 5th — half-diminished extended, a sophisticated minor-key ii chord.
Maintained for accuracy · Last updated July 2026 · How we review
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Cm11♭5
The C mi11♭5 chord is a six-note chord made up of C, E♭, G♭, B♭, D, and F. It is built from a root, minor third, diminished fifth, minor seventh, major ninth, and perfect eleventh.
Construction
C mi11♭5 = Root + Minor 3rd + Diminished 5th + Minor 7th + Major 2nd + Perfect 4th = C · E♭ · G♭ · B♭ · D · F
Note
Interval
Degree
C
Root
1
E♭
Minor 3rd
♭3
G♭
Diminished 5th
♭5
B♭
Minor 7th
♭7
D
Major 2nd
9
F
Perfect 4th
11
Key Signature
A chord has no key signature of its own, but the C mi11♭5 is the tonic (I) chord of C Major, whose key signature has no sharps or flats.
Chords in the Key of C Major
These are the triads built on each degree of the C major scale:
Keep going with the mi11♭5 chord — these pages cover the underlying theory, the connected reference material, and the practice tools that work with this chord.
The note names, intervals, fingering, and harmony on this chord page are grounded in the following sources. Public domain treatises and scores are linked to their full text; primary data is piano.org's own interval-derived reference dataset — continuously maintained and human-verified, with no fixed publication date.