A chromatic chord is any musical chord that includes at least one note not belonging in the diatonic scale associated with the prevailing key. In other words, at least one note of the chord is chromatically altered. Any chord that is not chromatic is a diatonic chord. Typical fingering for a second inversion C major chord on a guitar. ... In music theory, a diatonic scale (from the Greek diatonikos, to stretch out; also known as the heptatonia prima; set form 7-35) is a seven-note musical scale comprising five whole-tone and two half-tone steps, in which the half tones are maximally separated. ... In music theory, the key identifies the tonic triad, the chord, major or minor, which represents the final point of rest for a piece, or the focal point of a section. ... In music alteration, an example of chromaticism, is the use of a neighboring pitch in the chromatic scale in place of its diatonic neighbor such as in an altered chord. ...

For example, in the key of C major, the following chords (all diatonic) are among those that may be built on each degree of the scale:

• I: C maj7 [made up of the notes C-E-G-B]
• ii: D min7 [made up of the notes D-F-A-C]
• iii: E min7
• IV: F maj7
• V: G7
• vi: A min7
• vii: B min7♭5

However, a number of other chords may also be built on the degrees of the scale, and some of these are chromatic.

Examples:

bII in second inversion is called the Neapolitan sixth chord. For example in C Major: F-A♭-D♭. The Neapolitan Sixth chord resolves to the V. In music theory, a Neapolitan chord is a major chord built on the lowered second (supertonic) scale degree. ... Generally speaking, a sixth chord is any chord which contains the interval of a sixth. ...

IV# diminished chord is the Sharpened subdominant with diminished seventh chord. For example: F#-A-C-E♭. The #IV diminished chord resolves to the I. The Sharpened subdominant with added diminished seventh chord sounds a rather obscure chord name, and is more simply represented with the Roman notation #iv d7 (d7 is a superscript). ...

bVI: The Augmented sixth chords resolve to the V. An augmented sixth is one of three musical intervals that span six diatonic scale degrees. ...