Iii (III) Chord

Definition

The iii (III) chord is a triad built on the third scale degree of a diatonic scale, consisting of the root, major third, and perfect fifth. It often functions as a predominant chord, creating a smooth transition between tonic and dominant harmonies. The iii chord can add color and richness to harmonic progressions and is especially prominent in tonal music.

5 Must Know Facts For Your Next Test

1. In a C major scale, the iii chord is E minor (E-G-B), which consists of the notes E, G, and B.
2. The iii chord is often used to create smooth voice leading by connecting with both the tonic (I) and dominant (V) chords.
3. While the iii chord is less common as a tonic chord, it can serve as a substitute for the vi chord in many progressions.
4. In Roman numeral analysis, the iii chord is notated as 'iii' in minor keys and as 'III' in major keys.
5. The iii chord is frequently used in pop music to add emotional depth and variety to chord progressions.

Review Questions

• How does the iii (III) chord function in a harmonic progression?
  • The iii (III) chord serves primarily as a predominant chord, facilitating smooth transitions between tonic and dominant chords. For example, in a C major context, moving from E minor (iii) to A minor (vi) or G major (V) creates a sense of movement toward the dominant. This function adds richness to progressions by connecting different harmonic areas while maintaining a cohesive sound.
• Compare and contrast the roles of the iii (III) chord with the vi chord in diatonic harmony.
  • Both the iii (III) and vi chords are built on scale degrees that are closely related to the tonic and dominant chords. The iii chord often serves as a predominant that leads to the dominant, while the vi chord typically functions as a submediant that supports movement back to the tonic. In many cases, they can be interchangeable in progressions, though they may impart slightly different emotional qualities due to their unique placements within the harmonic structure.
• Evaluate the impact of using a iii (III) chord instead of a more common predominant chord in contemporary music compositions.
  • Using a iii (III) chord can significantly change the emotional landscape of contemporary music compositions. By substituting it for more conventional predominant chords like ii or IV, composers can introduce unexpected shifts that enhance tension or release. This alternative approach provides unique harmonic color and texture, making songs more memorable while still adhering to diatonic principles. As a result, this technique not only enriches musical phrases but also contributes to innovative songwriting styles.

Related terms

Diatonic Scale:

A seven-note scale that includes five whole steps and two half steps, forming the basis for the harmony of Western music.

Tonic:

The first note of a scale, serving as the home base or point of rest in tonal music.

Dominant:

The fifth scale degree of a diatonic scale, typically leading to the tonic and creating a strong resolution in harmony.