C9♯11: C Dominant 9th Sharp 11th Piano Chord

Construction

C 9♯11 = Root + Major 3rd + Perfect 5th + Minor 7th + Major 2nd + Diminished 5th = C, E, G, B♭, D, F♯

A chord has no key signature of its own, but the C 9♯11 is the tonic (I) chord of C Major, whose key signature has no sharps or flats.

These are the triads built on each degree of C Major:

I — C Major (major)

Degree	Numeral	Chord	Quality
1	I	C Major	Major
2	ii	D Minor	Minor
3	iii	E Minor	Minor
4	IV	F Major	Major
5	V	G Major	Major
6	vi	A Minor	Minor
7	vii°	B Diminished	Diminished

What is the C 9♯11 chord on piano?

The C 9♯11 chord contains the notes C – E – G – B♭ – D – F♯. On piano, play these notes together to sound the chord.