According to wikipedia, the boiling point of diethyl ether is 307,8 K, while the boiling point of pentane is 309,4 K. The difference between them is quite small, but I can't understand the fact that the boiling point of diethyl ether is lower one. While speaking about intermolecular forces, pentane molecules interact with each other using London forces only, while diethyl ether has oxygen atom which makes stronger London interaction because of greater electron number and ,although dipole moment might cancel out because of symmetry, oxygen atom still makes for molecules to form instantaneous dipole moments. I would like you to confirm whether my thinking is good or not? If not what could be the reason for this?