Final answer:
Carbon tetrachloride (CCl4) does not describe any of the molecules listed.
Step-by-step explanation:
The molecule that does not describe any of the molecules above is carbon tetrachloride (CCl4). Carbon tetrachloride is a covalent compound that consists of one carbon atom bonded to four chlorine atoms. It is used as a solvent, fire extinguishing agent, and in the production of refrigerants. None of the other molecules listed (CO2, PCl3, PCl5, SF6) match the description of carbon tetrachloride.