(musth1) Cadential 6/4 chords

The cadential 6/4 chord occurs as part of a two-chord progression of I6/4 – V (minor, i6/4). This two-chord progression happens at ends of phrases, and offers a melodic cadence (descending step-wise motion to 2 and/or 1), and occurs as part of a dominant harmony ending in either a half cadence or carrying on to resolution on tonic and an authentic cadence.

Some important things to keep in mind:

• The cadential 6/4 is not a tonic-functioning harmony, which is why we avoid labeling it with a RN of I (i). It really is part of a dominant function (the entire two-chord progression is D-Class).
• The cadential 6/4 always occurs on a strong beat (metrically).
• In four-voice partwriting, the bass of the 6/4 chord (scale degree 5) is always doubled. The other chord tones (scale degrees 3 and 1) are tendency tones.
• The tendency tones of a cadential 6/4 chord always resolve down by step from 3 – 2, and from 1 – LT.
• Both parts of the two-chord progression (C6/4 to V) have scale degree 5 in the bass.
• The cadential 6/4 to dominant progression functions the same way that a root position V chord would. The C6/4 progression never occurs as part of a tonic prolongation.