The split complimentary color scheme uses colors near the opposite side of the color wheel. So instead of using the compliment green in it's purest form, the colors used will be green-blue and yellow-green. The green is "inferred" and does not tend to clash as much as a straight complimentary scheme. This palette makes use of subtle warm and cool shades. It is my personal favorite because it yields so many lovely hues.
These are examples of Red's Split complimentary schemes.