semicord

D#m7b5 D# half-diminished seventh chord

Notes
D# F# A C#
Formula
1 b3 b5 b7
Semitones
0 3 6 10 above the root
Also written
Ebm7b5 (Eb Gb Bbb Db)
Other symbols
D#ø7, D#ø, D#m7(b5), D#min7b5

D# to F# is a minor third (3 semitones), F# to A is a minor third (3 semitones), A to C# is a major third (4 semitones). A diminished triad plus a minor seventh, C#, so D# to A is a tritone. It is also called half-diminished: the fully diminished D#dim7 has a diminished seventh (9 semitones) instead. With F# in the bass the same four keys read as F#m6.

D#m7b5 on the piano

C4D4E4F4G4A4B4C5D5E5F5G5A5B5C#4D#4F#4Ab4Bb4C#5Eb5F#5Ab5Bb5C4D#F#AC5C#

Root position from D#4: D#4, F#4, A4, C#5. Middle C is C4.

D#m7b5 on the guitar

Standard tuning (E A D G B E). Strings run low E on the left to high e on the right, frets downwards; × is a muted string, ○ an open string, and each dot shows the note it sounds, with the root in blue-green. Every shape below has D# as its lowest note.

6fr×D#D#AAC#C#F#F#×
A-shape barre, root on the A string at fret 6
x 6 7 6 7 x (low E to high e)
Sounds D#3 A3 C#4 F#4
10frD#D#×C#C#F#F#AA×
E-shape, root on the E string at fret 11
11 x 11 11 10 x (low E to high e)
Sounds D#3 C#4 F#4 A4

The E-shape and A-shape grips are movable: an E-shape chord's root is the note under your first finger on the low E string, an A-shape chord's root is the note on the A string. Slide the same grip up or down to play half-diminished seventh chords on other roots.

Inversions of D#m7b5

An inversion puts a note other than the root in the bass. The name is what semicord's chord finder calls those notes played bottom to top; a slash name like C/E means a C chord with E in the bass.

PositionNotes, bass firstNamedListen
Root positionD# F# A C#D#m7b5
1st inversionF# A C# D#F#m6 (also read as D#m7b5/F#)
2nd inversionA C# D# F#D#m7b5/A
3rd inversionC# D# F# AD#m7b5/C#

Where D#m7b5 fits

D#m7b5 is viiø7 in E major, iiø7 in C# minor. As iiø7 it opens the minor ii–V–i: D#m7b5 → G#7 → C#m, the minor-key twin of the ii–V–I.