Space plays and stops
- Notes and intervals
- C#M3E#m3G#m3B
C# Dominant 7, written C#7, is built from C#, E#, G# and B: the root, major 3rd, 5th and minor 7th.
Its 3rd and 7th, E# and B, are its guide tones: they say what kind of chord it is, so voicings are built around them and the root is often left to the bass. G7, a tritone away, has the same two notes the other way up, so it can stand in for C#7 as its tritone substitute.
In the progressions here, C#7 is the V7 of the Major ii-V Progression in F#, the VI7 of the Major I-VI-ii-V Progression in E, the III7 of the Cycle of Dominants in A, the II7 of the Whole-Step ii-V Chain in B and the VII7 of the Coltrane Changes in D.