Diatonic chords are the chords that can be made using the notes of a particular scale or key.
Knowledge of diatonic chords is useful in improvising. If you can identify which chords belong to which key, you’ll be able to select a suitable scale to solo with.
Knowledge of diatonic chords can help in songwriting, and will also improve your understanding of harmony.
In this article, we’ll examine the diatonic triads and diatonic seventh chords of every major scale.
The chords in C major (formed from a C major scale) are shown below:
Diatonic Chords – Triads
Diatonic chords are the chords that can be made from the notes of a particular scale. Therefore, chords diatonic to a C major scale are built from the seven notes of that scale, namely C, D, E, F, G, A, B.
We’ll start by looking at diatonic triad chords, which contain three notes each. There are seven possible diatonic triads using the notes of a major scale; each note of the major scale becomes the root note of one of these chords.
The diatonic triads of a C major scale are C major, D minor, E minor, F major, G major, A minor and B diminished:
D Major Diatonic Chords
In a D major scale, the diatonic chords are D major, E minor, F# minor, G major, A major, B minor and C# diminished. Notice that the order of the type of diatonic triads does not change, only the root notes. The order of the diatonic chords of a major scale is:
The following diagrams will help to explain this:
Diatonic Triads – All Major Keys
Below is a chart showing all of the diatonic triads in each major key:
Notes On Diatonic Triads
Triad chords contain three notes, the outer two of which are a fifth (perfect, diminished or augmented) apart. There are four kinds of triad: major, minor, diminished and augmented.
The interval between the first and second notes is a major third in major and augmented triads and a minor third in minor and diminished triads. The interval between the second and third notes is a minor third in major and diminished triads and a major third in minor and augmented triads.
Triads can also be inverted, which means that the third or fifth becomes the lowest note of the chord, rather than the root. In first inversion, the third is the lowest note. In second inversion, the fifth is the lowest note. The diagram below shows a C major triad in root position, first inversion and second inversion.
Diatonic Seventh Chords
The triad built from the fifth degree of the scale (i.e. G in a C major scale) is often extended to include the seventh note. This produces a dominant seventh chord, which is an important chord harmonically as it creates a strong pull back to the root triad. The other diatonic chords can also be extended in this manner, to create diatonic seventh chords. These chords are often used to harmonize melodies in jazz.
In a major scale, the order of diatonic seventh chords is:
1. Major 7th
2. Minor 7th
3. Minor 7th
4. Major 7th
5. Dominant 7th
6. Minor 7th
7. Half-Diminished 7th (Minor 7th Flat 5)
Diatonic Seventh Chords In Every Key
Using Diatonic Chords In Songwriting
There are many different approaches to writing songs, and there is no right or wrong way. However, knowing about music theory and the notes present in certain scales and keys can help you to create and harmonize melodies faster.
If you have come up with a good melody, perhaps by jamming over chords with lyrics you have already written, then you can try harmonizing it with diatonic chords.
For example, suppose that you have written a melody in C major over a repeated C to F chord progression. You could, at various points in the song, try playing an Am in place of the C chord, or a Dm in place of the F.
Both of these minor chords are diatonic to the scale of C, and could possibly add another dimension to the music.
You could also experiment with playing the diatonic 7th versions of the chords.
Both of these ideas may or may not fit with the song, but knowing diatonic chords gives you some useful tools to experiment with, and may help you to find that extra something that makes a good song into a great one.
You could also try adding some non-diatonic chords into your songs. Use chords that include the notes of your melody. For example, if your song is in the key of C major, and your melody note is an E, try playing an A major chord underneath it.
The A chord isn’t diatonic (there isn’t a C sharp in a C major scale), but you may find that your song is suddenly given a harmonic twist that you hadn’t considered before.
As you experiment, you’ll begin to find new ways of harmonising your songs. This technique can separate the best songwriters from the herd, and it all stems from having a knowledge of diatonic chords.