The abbreviation THF and the CH8O formula, which forms a pentagon ring that has oxygen at its corners, is a solvent used in the resin industry and has a liquid temperature of 65-65 degrees Celsius. Tetra- hydrofranane is a ring either. The Ether formula is ROR. That is the two R groups that are connected to oxygen. Now if they are circular, they are circular ether. It is a very good solvent for organic reactions. (The ethers usually do not react much and they are used more often as solvents (the tetrahydrofuran from the eruption, which is available in a compound, has two bonds, and it is converted into tetrahydrofuran by giving 4hydrogen