The second inversion of a chord is the voicing of a triad, seventh chord, or ninth chord in which the fifth of the chord is the bass note. In this inversion, the bass note and the root of the chord are a fourth apart which traditionally qualifies as a dissonance. There is therefore a tendency for movement and resolution. In notation form, it is referred to with a c following the chord position (For e.g., Ic. Vc or IVc) or as a 6
4 chord (as in I6
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.
Note that any voicing above the bass is allowed. A second inversion chord must have the fifth chord 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 G dominant seventh chord, the bass note is D, the fifth of the seventh chord.
Cadential second-inversion chords are typically used in the authentic 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 a cadential 6
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
The cadential 6
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 involving voice leading above a stationary bass.
- In the first designation, the cadential 6
4 chord features the progression: I6
4-V-I. Most older harmony textbooks use this label, and it can be traced back to the early 19th century.
- In the second designation, this chord is not considered an inversion of a tonic triad but as a dissonance resolving to a consonant dominant harmony. This is notated as V6–5
4–3-I, in which the 6
4 is not the inversion of the V chord but a double appoggiatura on the V that resolves down by step to V5
3 (that is, V6
4-V). This function is very similar to the resolution of a 4–3 suspension. Several modern textbooks prefer this conception of the cadential6
4, which can also be traced back to the early 19th century.
In a progression with a passing second-inversion chord, the bass passes between two tones a third apart (usually of the same harmonic function). When moving from I to I 6, the passing chord V6
4 is placed between them – though some prefer VII 6 to V6
4 – creating stepwise motion in the bass (scale degrees
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. The upper voices usually move in step (or remain stationary) in this progression.
Auxiliary (or pedal)
In a progression with an auxiliary (or pedal) second-inversion chord, the IV6
4 chord functions as the harmonization of a neighbor 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 this progression, the bass arpeggiates 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.
- Hubbard, William Lines (1908). The American History and Encyclopedia of Music, Vol. 10: Musical Dictionary, p.103. Irving Squire: London. [ISBN unspecified]. Also at the HathiTrust Digital Library
- Weber, Theory of musical composition, p. 350, quoted in Beach, D (1967) "The functions of the six-four chord in tonal music", Journal of Music Theory, 11(1), p. 8
- Aldwell, Edward; Schachter, Carl (1989), Harmony and Voice Leading (2nd ed.), San Diego, Toronto: Harcourt Brace Jovanovich, p. 263, ISBN 0-15-531519-6, OCLC 19029983,
The chord does not act as an inversion of I 5LCC MT50 A444 1989.
3; it serves neither to extend it nor to substitute for it.
- Forte, Allen (1974), Tonal Harmony in Concept and Practice (2nd ed.), NY: Holt, Rinehart and Winston, p. 68, ISBN 0-03-077495-0.
- Arnold, F.T. The art of accompaniment from a thorough-bass, Vol. 1, p. 314. ISBN 0-486-43188-6. quoted in Beach, David (1967). "The functions of the six-four chord in tonal music", p.7, Journal of Music Theory, 11(1).
- Gauldin, Robert (1997). Harmonic Practice in Tonal Music New York: W.W. Norton & Company, pg 273. ISBN 0-393-97666-1
- Walter Piston, Harmony
- Aldwell and Schachter, Harmony and Voice Leading, 3rd Edition