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

When rooted in C, the mystic chord consists of the pitch classes C, F♯, B♭, E, A, and D.

This is often interpreted as a quartal hexachord consisting of an augmented fourth, diminished fourth, augmented fourth, and two perfect fourths. The chord is related to other pitch collections. For example, it is a hexatonic subset of the overtone scale, also known in jazz circles as the Lydian dominant scale, lacking the perfect fifth.