text: It could be glass (or amorphous solid) which is considered to be a state or phase between solid and liquid.\n\nIf you're looking for something beyond plasma, that question gets pretty tricky to answer because it's quite subjective. You've got quark-gluon plasma, superfluids and loads of other stuff. Some of them haven't existed since the big bang. Some are theoretical. A lot depends on how you define state so take yer pick!\n\nBy the way, contrary to what the answer above says, carbon dioxide can form a liquid phase; just not at atmospheric pressure. At high pressure (over 5 atmospheres) it will form a liquid phase. This to do with triple points and all that sort of thing.\n\nEDIT: a triple point is where gas, liquid and solid phases exist in thermodynamic equilibrium. Triple points are part of a phase diagram and phase diagrams describe how a substance's phases behave under different conditions. \n\nWater's triple point occurs at 0.01 C, 0.006 atm. It definitely does not form a super critical fluid under those conditions. Are you sure you're not confusing the triple point and the CRITICAL POINT (which is where liquid and gas cannot be distinguished: this is the start of the super critical region)?\n\nDon't believe me? Check the links. The last one is for some lozenges for that nasty cough you've picked up ;) ...