Now as we understand how we see light, how color actually works, what the visible spectrum is, It's time that we look at how we create sensible color matches, There is a bit of science to it and all this has to do with color wheel.
A color wheel (also referred to as a color circle) is a visual representation of colors arranged according to their chromatic relationship.
a complementary color palette is made using colors that are opposite to each other on color wheel
Double Complementary Color Relationship
A double complementary color palette is a group of color close to each other on the other wheel.
Split Complementary Color Relationship
The split-complementary color scheme is a variation of the complementary color scheme. In addition to the base color, it uses the two colors adjacent to its complement.
Thats all for the basic of Relationships of Colors. There is a lot more resource available on the web for deeper understanding, here is a Youtube Link for more visual guide.