structural:expansion, quality:correction, stylistic:style_transfer
Harmonic content

The notes of a chord form intervals with each of the other notes of the chord in combination. A 3-note chord has 3 of these harmonic intervals, a 4-note chord has 6, a 5-note chord has 10, a 6-note chord has 15. The absence, presence, and placement of certain key intervals plays a large part in the sound of the chord, and sometimes of the selection of the chord that follows.

A chord containing tritones is called tritonic; one without tritones is atritonic. Harmonic tritones are an important part of dominant seventh chords, giving their sound a characteristic tension, and making the tritone interval likely to move in certain stereotypical ways to the following chord. Tritones are also present in diminished seventh and half-diminished chords.

A chord containing semitones, whether appearing as minor seconds or major sevenths, is called hemitonic; one without semitones is anhemitonic. Harmonic semitones are an important part of major seventh chords, giving their sound a characteristic high tension, and making the harmonic semitone likely to move in certain stereotypical ways to the following chord. A chord containing major sevenths but no minor seconds is much less harsh in sound than one containing minor seconds as well.

Other chords of interest might include the