An ether molecule has an oxygen atom connected to two alkyl (see hydrocarbon) units through carbon-oxygen single bonds. The two alkyl groups can be the same or different: The following are NOT examples of ethers because the oxygen atom is not connected to two different carbon atoms via single bonds or because the attached group is not an alkyl. Ether is also used as shorthand to refer to one of the most common ethers, diethyl ether, shown above. Additional Info: Peroxide Formation Ethers are particularly prone to formation of dangerous peroxides. Anyone using an ether should Read The Section on Peroxides First. An Ether That is Not An Ether. The term "petroleum ether" is an old term used to refer to a mixture of hydrocarbons with a specific boiling point range. In other words, there is no ether in petroleum ether! Synonyms for petrolem ether include naphtha, petroleum benzin, benzin, and the lab slang, "pet ether". The petroleum ether most commonly used in laboratories has a boiling point range of roughly 30 to 60 ^oC