Mystic chord

In music, the mystic chord or Prometheus chord is a six-note synthetic chord and its associated scale, or pitch collection; which loosely serves as the harmonic and melodic basis for some of the later pieces by Russian composer Alexander Scriabin. Scriabin, however, did not use the chord directly but rather derived material from its transpositions.

It consists of the pitch classes: C, F♯, B♭, E, A, D. This is often interpreted as a quartal hexachord consisting of an augmented fourth, diminished fourth, augmented fourth, and two perfect fourths. However, the chord may be spelled in a variety of ways, and it is related to other pitch collections, such as being a hexatonic subset of the Overtone scale, lacking the perfect fifth.

Nomenclature

The term "mystic chord", appears to derive from Scriabin's intense interest in Theosophy, and the chord is imagined to reflect this mysticism. It was coined by Arthur Eaglefield Hull in 1916.

It is also known as the "Prometheus chord", after its extensive use in his work Prometheus: The Poem of Fire, Op.60. The term was invented by Leonid Sabaneyev.