Roman numeral analysis of chord with non-chord tone in bass

Question

We use figured bass notation to help indicate chords in inversion by establishing the interval between the bass note and the other notes of the chord. I have seen figured-bass symbols applied to major triads, resulting in the "five-three" chord (root position), the "six-three" (3rd in bass), the "six-four" (5th in bass), as well as to 7th chords, giving us the "seven", "six-five", "four-three", and "four-two chords". Forgive me if this explanation is too brief or if you prefer different nomenclature.

For analysis, I prefer using roman numeral notation instead of "slash" notation, in which the chords are named . . . by name. For example, a I63 chord in C major would be written as "C/E". Now, depending on the song, there may be chords that have neither non-chord tones nor the 7th of the chord in the bass, such as a C major chord with a D in the bass. In slash notation, this would be a "C/D". How would this be written in roman numeral/figured bass notation? Note: please treat this C/D example, along with any chord with scale degree 2, 4, or 6 in the bass, as an actual chord, rather than a chord with a counter-melody moving in the bass line--I am not thinking of the bass as a passing tone here.

Is there a procedure for naming chords with scale degrees 2, 4, or 6 in the bass? Please let me know.

Best,

286642

Answer 1

The figures would still reflect the intervals above the bass, so X[7-4-2] or, possibly, X[9-7-4]. The Roman numeral would depend on the context. In common practice harmony C/D would be some kind of suspension, so X would be the chord of resolution. X cannot be determined from the information given in the OP. At minimum, we need to know the key and the next chord, if not additional chords before and after.

Roman numeral analysis is context dependent.