To demonstrate how much confusion there is about color just select Google Images on your computer and type color wheel in the search box.
You will be amazed at how many different presentations of the color wheel there are to addle your brain.
I offer here my understanding of the subject. I believe this to be an adequate, correct color wheel here:

The large circles painted yellow, magenta and cyan are to remind us that these are the primary colors derived from blending the three colors of sunlight as seen in a prism generated spectrum.
If the spectrum is projected too close to the prisim you will see a bright white football shape in the middle of the colors because all three colors overlap in that part of the image. A photo of that effect here:

If you project the spectrum on a surface farther from the prism you will see the three colors of light separated without any bright white portion. We customarily refer to these three colors as red, blue, and green even though they are not the same red, blue, and green we were taught in elementary school. The green circle in the center overlaps the red on the left to make yellow and it overlaps the blue on the right to make cyan.

Painters make secondary colors by mixing any two of the three primary color pigments. The secondary colors are represented by “surf-board” shapes of orange, violet and green illustrated in the color wheel.
Tertiary colors are made by mixing more adjacent primary color with an adjacent seconday color. In this way we are able to produce yellow-orange, red-orange, red-violet, blue-violet, blue-green and yellow-green.
The black disc in the center is made by mixing all three primary colors together using thick paint.
Try it yourself with water colors. Do not use any black or white. You will be able to reproduce an accurate, clean and rather beautiful color wheel of your own.
If any paint color seems too powerful, dilute it slightly with a very small amount of water.
Notice that warm colors contain more yellow and cool colors contain more blue.
A line drawn through the magenta and green portions of the wheel separate the warm from the cool colors. I think of magenta and green “tepid” colors.
It is often useful to create impure (“grayed” or “neutralized”) colors by adding a complimentary color to any chosen color on the color wheel. Complimentary colors are opposite each other on the color wheel.
You may have to make several attempts at producing your own color wheel. Eventually you will get it “right” and have something you can refer to for the rest of your painting career.
Arty 6-9-09