Chord category

Altered chords

An altered chord is a dominant with a modified fifth or extensions: ♭5, ♯5, ♭9, ♯9. They maximise tension before resolving — the sound of modern jazz.

C7♭5D7♭5E7♭5F7♭5G7♭5A7♭5B7♭5

Theory

C7♭5 is a C7 with a diminished fifth; C7♯5 raises it. Both call for resolution to the tonic.

Scale C whole-tone · C – D – E – F♯ – G♯ – A♯
CDECDECF♯G♯A♯F♯G♯A♯
C7♭5 · C · E · F♯ · A♯
C seventh flat five — C, E, F♯, A♯CEF♯A♯

Formula and steps

Degrees

1 – 3 – ♭5 – ♭7

Steps (semitones)

4 – 2 – 4

How they are used

Used on the V degree to intensify the resolution. The whole-tone and altered scales are their natural companions.

Progressions (roman numerals)

  • ii – V7♭5 – I
  • ii – V7♯5 – i

Example sequences

  • Dm – G7♭5 – C
  • Dm – G7♯5 – Cm

Related chords

C7C dominant seventhC · E · G · A♯C7♯5C seventh sharp fiveC · E · G♯ · A♯Cm7♭5C half-diminishedC · D♯ · F♯ · A♯Cdim7C diminished seventhC · D♯ · F♯ · A

Alternative symbols

Written by noting the alteration in parentheses: C7(♭5), C7(♯5), C7(♭9). C7♯5 coincides with the augmented seventh.

Chord categories

MajorMinorSeventhExtendedSuspendedDiminishedAugmentedAddedAltered