An added sixth chord ends songs including Hank Williams' "Hey, Good Lookin'", Carl Perkins' "Movie Magg" and "Blue Suede Shoes", Ronnie Hawkins' "Red Hot", Chuck Berry's "Rock and Roll Music", Scotty Moore's accompaniment in Elvis Presley's "That's All Right (Mama)", and the Beatles' "She Loves You" and "Ballad of John and Yoko."
The thirds in a mixed third chord, a chord which includes as its third both the major and minor third (for a chord on C: C E♭ E G), are usually separated by an octave or more (Marquis 1964):
An example of an added tone chord may be found in Igor Stravinsky's Symphony of Psalms (see Marquis 1964) while an added tone (G) chord with mixed thirds, a major third and minor third, by William Schuman (ibid).
An added tone, such as that added a perfect fourth below the root, may suggest polytonality (ibid) and the practice of adding tones may have led to superimposing chords and tonalities though added tone chords have most often been used as more intense substitutes for traditional chords (Jones, ibid). For instance a minor chord that includes a major second interval while still retaining its minor third holds a great deal more dramatic due to the very close intervals of the major 2nd and minor 3rd. A major chord with an added major second sounds a great deal more pleasant and serene than its basic counterpart.