also plasma is not a gas, it’s a distinct form of matter different from a gas
four states of matter exist: solid, liquid, gas, and plasma
“Many places teach that there are three states of matter; solid, liquid and gas, but there are actually four. The fourth is plasma. To put it very simply, a plasma is an
ionized gas, a gas into which sufficient energy is provided to free electrons from atoms or molecules and to allow both species, ions and electrons, to coexist.”
http://education.jlab.org/qa/plasma_01.html