Summary of Chromatic Scale Degree Functions

A. Chromatic scale degrees often occur without harmonic support, i.e. as chromatic passing tones or neighbor (usually lower neighbors). Chromatic lower neighbor tones have a quasi-leading tone function, since they resolve upwards to relatively stable, diatonic degrees. The term "microtonicization" is sometimes used for this effect.

B. Raised degrees most often function as applied leading tones. Thus,

(1) s4 => tonicization of V; s5 => tonicization of vi, etc.

(2) In minor, raised 6 and 7 represent the inflected scale forms (harmonic and melodic minor).

(3) Augmented triads often result from the raising of the fifth of a major triad, with the intention of creating a lower leading tone to the third of the triad whose root is a fifth lower: A C major triad, for example, moves more urgently to an F major triad if its fifth is raised (C-E-G#, with the latter two pitches resolving by step to F and A).

C. The functions of lowered degrees are more varied. Most common are:

(1) In major,

f6 => mixture, usually in pre-dominant chords (iio6, iv)

f3 (and sometimes f7 as well) => mixture in tonic, mediant and submediant chords (i, fIII, fVI)

(2) In major or minor,

f7 => tonicization of IV (since f7 forms the 7th of V7/IV)

f2 almost always indicates the Neapolitan (fII, fII6). To use the Neapolitan in major, f6 must also be introduced.

D. f6 (usually in the bass) plus s4 form an augmented sixth; in minor, s4 together with diatonic 6 creates the same interval. All augmented sixth chords contain these scale degrees plus the tonic scale degree:

 

Nationality

Scale degrees (the usual bass note is given first)

Italian

f6, #4, 1

French

f6, #4, 1, 2

German (in minor)

f6, #4, 1, 3

German (in major)

f6, #4, 1, #2

E. Other chromatic degrees may function in common-tone chords (e.g. fully diminished sevenths) and altered dominants (e.g. apparent French augmented sixth chords "applied to" I).