CHAPTER 10 - CHORDS IN 2^ND INVERSION

The 2nd inversion of consonant triads (with a perfect 5th) is used in a very restrictive way in tonal music. This chapter describes the main formulas under which this chord is used.

1. GENERAL CONSIDERATIONS OVER THE 2^ND INVERSION OF CONSONANT TRIAD

- We say that a consonant triad is in 2nd inversion when its fifth is located in the bass. We call it "6/4 chord", and it is notated with the figures 6 and 4.

- In classical tonal music, the 2nd inversion of the consonant triad IS NOT USED. This could be the end of the chapter. However, there are a few, very exceptional formulas that appear in tonal music from time to time, which do have the appearance of consonant triads in 2nd inversion. They all have the following characteristics in common:

A - They are generated by the superposition of non-chord tones. For this reason, they are somehow fictitious chords and their harmonic function is modified or blurred with respect to the "basic harmonic system". That is why they are written in brackets.

B - In all of them, the bass note is normally doubled, i.e. the fifth of the chord.

- The most common of these formulas are listed below, in order of relevance with respect to their frequency in tonal music.

2. THE CADENTIAL 6/4

- This is the most commonly used 6/4 chord.  It is formed by placing two simultaneous appoggiaturas on the dominant chord. Although it has the appearance of a I degree, its function is still dominant (non-chord tones never change the harmonic function).

Im. 10-2

- The appoggiatura of the leading tone always resolves downwards towards it. The other appoggiatura can move:

- Case a: downwards, towards the 5th of the dominant chord.

- Case b: upwards, towards the 7th of the dominant chord.

- The cadential 6/4 is used, as the name suggests, to reinforce the dominant function in a perfect (or deceptive) cadence. As you can see in the example, it is typical for the bass to leap an octave down.

- Sometimes, the cadential 6/4 leads to the 3rd inversion of the dominant 7th chord, thus generating an imperfect cadence. You can see this in case c.

3. THE NEIGHBOURING 6/4

- The neighbouring 6/4 is created by placing two simultaneous upper neighbour tones on the 3rd and 5th of a triad in root position. This creates the impression of a chord in 2nd inversion, but, like the other 6/4 cases, it has no harmonic function. You can see this in the examples.

Im. 10-3

4. THE PASSING 6/4

- The passing 6/4 is a consonant triad in 2nd inversion in which passing notes prevail. There are several possibilities, but the most common is the one known as "voice exchange".

- "Voice exchange" is a pattern in which a triad chord shifts between the root position and the 1st inversion, or vice versa.  

- As you can see in the examples, in the "voice exchange" pattern there is an intermediate chord, in 2nd inversion, formed by 2 passing tones and one neighbour tone.

- The formula is always the same:

A - One voice moves in contrary motion to the bass. 

B - Another voice, singing the root of the chord, sings a lower neighbour tone. 

C - And another voice, singing the 5th of the chord, remains still

Im. 10-4

5. SUGGESTED EXERCISES

- Harmonise the following soprano lines in 4 parts, including 6/4 sonorities as indicated.

 3.  Write a harmonic structure with the following features:

- Key: A major

- Time signature: 3/4

- Form: 3 phrases of 4 measures (12 measures in total)

- Cadences (at the end of each phrase): Imperfect, Half, Perfect

- Harmonic rhythm: quarter notes

- Include, at least, 2 secondary dominants

- Include at least one 6/4 chord of each of the types described in this chapter.