Diminished chord.html



A diminished triad chord ( Play (help·info)) is a triad consisting of a minor third and a diminished fifth above the root — if built on C, a diminished chord would have a C, an E♭ and a G♭. It resembles a minor triad with a lowered (or diminished) fifth.

In the common practice period, the diminished chord is considered dissonant, or unstable. It lacks tonal center or drive because the diminished fifth symmetrically divides the octave.

A diminished chord occurs in a major scale only on the seventh scale degree; in the key of C, this is a B diminished chord (B, D, F). This also occurs in the seventh chord built on the fifth note; in C, this is G dominant seventh (G, B, D, F).

In a twelve-tone equal tempered tuning, a diminished chord has 3 semitones between the third and fifth, 3 between the root and third, and 6 between the root and fifth. It is represented by the integer notation 0, 3, 6.

In most sheet music books, Cdim or C° denotes a diminished seventh chord (a four note chord) with root C, and Cm-5 or Cmb5 denotes a diminished triad with root C. Howevever, in some modern jazz books and some music theory literature, Cdim or C° denotes a diminished triad, while Cdim7 or C°7 denotes a diminished seventh chord.

See also half-diminished seventh chord.