In music theory

Music theory

Music theory is the study of how music works. It examines the language and notation of music. It seeks to identify patterns and structures in composers' techniques across or within genres, styles, or historical periods...

, the leading-tone seventh chords are vii⁷ and vii⁷, the half-diminished

Half-diminished seventh chord

In music theory, the half-diminished seventh chord is created by taking the root, minor third, diminished fifth and minor seventh of any major scale; for example, C half-diminished is . Its consecutive intervals are minor 3rd, minor 3rd, major 3rd...

 and diminished

Diminished seventh chord

A diminished seventh chord is a four note chord that comprises a diminished triad plus the interval of a diminished seventh above the root. Thus it is , or enharmonically , of any major scale; for example, C diminished-seventh would be , or enharmonically...

 seventh chord

Seventh chord

A seventh chord is a chord consisting of a triad plus a note forming an interval of a seventh above the chord's root. When not otherwise specified, a "seventh chord" usually means a major triad with an added minor seventh...

s on the seventh scale degree

Degree (music)

In music theory, a scale degree or scale step is the name of a particular note of a scale in relation to the tonic...

, or leading-tone

Leading-tone

In music theory, a leading-note is a note or pitch which resolves or "leads" to a note one semitone higher or lower, being a lower and upper leading-tone, respectively....

, in major

Major scale

In music theory, the major scale or Ionian scale is one of the diatonic scales. It is made up of seven distinct notes, plus an eighth which duplicates the first an octave higher. In solfege these notes correspond to the syllables "Do, Re, Mi, Fa, Sol, La, Ti/Si, ", the "Do" in the parenthesis at...

 and harmonic minor, resolving

Resolution (music)

Resolution in western tonal music theory is the move of a note or chord from dissonance to a consonance .Dissonance, resolution, and suspense can be used to create musical interest...

 to the tonic

Tonic (music)

In music, the tonic is the first scale degree of the diatonic scale and the tonal center or final resolution tone. The triad formed on the tonic note, the tonic chord, is thus the most significant chord...

. Leading-tone triads and seventh chords are frequently substituted

Chord substitution

In music theory, chord substitution is the use of a chord in the place of another related chord in a chord progression. Jazz musicians often substitute chords in the original progression to create variety and add interest to a piece. The substitute chord must have some harmonic quality and degree...

 for dominant chords

Dominant (music)

In music, the dominant is the fifth scale degree of the diatonic scale, called "dominant" because it is next in importance to the tonic,and a dominant chord is any chord built upon that pitch, using the notes of the same diatonic scale...

, with which they have three common tone

Common tone

In music a common tone is a pitch class that is a member of, or common to, a musical scale and a transposition of that scale, as in modulation...

s, for variety.

The leading-tone seventh chord is half diminished

Half-diminished seventh chord

In music theory, the half-diminished seventh chord is created by taking the root, minor third, diminished fifth and minor seventh of any major scale; for example, C half-diminished is . Its consecutive intervals are minor 3rd, minor 3rd, major 3rd...

 in C major (B-D-F-A) and fully diminished

Diminished seventh chord

A diminished seventh chord is a four note chord that comprises a diminished triad plus the interval of a diminished seventh above the root. Thus it is , or enharmonically , of any major scale; for example, C diminished-seventh would be , or enharmonically...

 in C minor (B-D-F-A). However, composers throughout the Common practice period

Common practice period

The common practice period, in the history of Western art music , spanning the Baroque, Classical, and Romantic periods, lasted from c. 1600 to c. 1900.-General characteristics:...

 often employed modal mixture

Borrowed chord

A borrowed chord is a chord borrowed from the parallel key . Borrowed chords are typically used as "color chords", providing variety through contrasting scale forms, major and the three forms of minor...

 when using the leading-tone seventh chord in a major key, allowing for the substitution of the half-diminished seventh chord for the fully diminished seventh chord. This mixture is commonly used when the leading-tone seventh chord is functioning as a secondary leading-tone chord

Secondary leading-tone chord

In music theory, a secondary leading-tone chord or secondary seventh or secondary diminished seventh, as in seventh scale degree or leading-tone, is a secondary chord but rather than being a dominant it is a leading-tone seventh chord or triad, which are similar in function to dominant chords. Also...

. The leading-tone seventh chord contrasts with the subtonic seventh chord in that the subtonic has a flatted seventh (chord root): in C minor, B-D-F-A.