As the IV degree (subdominant), a major chord can resolve to V or directly to I (plagal cadence).
Features
Character
Half-diminished, with an added 9th
Characteristic interval
Diminished 5th (b5), 9th
Description
The minor 3rd, diminished 5th, and minor 7th form a half-diminished seventh chord; the major 9th adds a diatonic extension. The b5 dissonance preserves the instability of the core.
Application
ii-V in minor (extended)
Modern jazz
Substitute for m7b5 with ninth
Voicing & structure
Root position
v1Eb(Eb4)Bass
root
v2Gb(Gb4)m3from Eb
v3A(A4)m3from Gb
v4Db(Db5)M3from A
v5F(F5)M3from Db
Harmony
Compatible scales
All chord tones are contained in these scales — use them for improvisation.