Thesecondinversion of achord is thevoicing of atriad,seventh chord, orninth chord in which thefifth of the chord is thebass note. In this inversion, the bass note and theroot of the chord are afourth apart which traditionally qualifies as adissonance. There is therefore a tendency for movement and resolution. In notation form, it may be referred to with a c following the chord position (e.g., Ic. Vc or IVc).[1] Infigured bass, a second-inversion triad is a6
4 chord (as in I6
4), while a second-inversion seventh chord is a4
3 chord.
Inversions are not restricted to the same number of tones as the original chord, nor to any fixed order of tones except with regard to the interval between the root, or its octave, and the bass note, hence, great variety results.[2]
Note that any voicing above the bass is allowed. A second inversion chord must have the fifthchord factor in the bass, but it may have any arrangement of the root and third above that, including doubled notes, compound intervals, and omission (G-C-E, G-C-E-G', G-E-G-C'-E', etc.)
In the second inversion of a C-major triad, the bass is G — the fifth of the triad — with the root and third stacked above it, forming the intervals of a fourth and a sixth above the inverted bass of G, respectively.
In the second inversion of a Gdominant seventh chord, the bass note is D, the fifth of the seventh chord.
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There are four types of second-inversion chords:cadential,passing,auxiliary, and bassarpeggiation.
Cadential second-inversion chords are typically used in theauthentic cadence I6
4-V-I, or one of its variation, like I6
4-V 7-I. In this form, the chord is sometimes referred to as acadential6
4 chord. The chord preceding I6
4 is most often a chord that would introduce V as a weak to strong progression, for example, making -II-V into II-I6
4-V or making IV-V into IV-I6
4-V.
The cadential6
4 can be analyzed in two ways: the first labels it as a second-inversion chord, while the second treats it instead as part of a horizontal progression involvingvoice leading above a stationary bass.
In a progression with a passing second-inversion chord, the bass passes between two tones a third apart (usually of the sameharmonic function[7]). When moving from I to I 6, thepassing chord V6
4 is placed between them – though some prefer VII 6 to V6
4 – creatingstepwise motion in the bass (scale degrees
–
–
). It can also be used in the reverse direction: I 6-V6
4-I. The important point is that the V6
4 chord functions as a passing chord between the two more stable chords. It occurs on the weaker beat between these two chords.[7] The uppervoices usually move in step (or remain stationary) in this progression.
In a progression with an auxiliary (or pedal) second-inversion chord, the IV6
4 chord functions as the harmonization of aneighbor note in the progression, I-IV6
4-I. In this progression, the third and fifth rise a step each and then fall back, creating a harmonization for the scale degrees
–
– in the top voice.
In this progression, the bassarpeggiates the root, third, and fifth of the chord. This is just a florid movement but since the fifth is present in the bass, it is referred to as a bass arpeggiation flavour of the second inversion.[citation needed]
The chord does not act as an inversion of I5LCC MT50 A444 1989.
3; it serves neither to extend it nor to substitute for it.
