Additional 6/4 chords are non-cadential chords that serve as passing or embellishing tones within a musical passage. They are typically used for harmonic variety and can add color or tension to the overall harmony.
Related terms
Passing Tone: A non-chord tone that connects two harmonically important tones by stepwise motion.
Embellishing Tone: Non-chord tones that decorate or enhance melodic lines without altering underlying harmony.
Suspension: A type of embellishing tone where a note from the previous chord is held over into the next chord, creating a temporary dissonance before resolving.