Chemical compounds are formed of two or more chemical elements, and so their boiling and melting points are affected by the manner in which those atomic elements react with heat, cold, and each other.
The melting point of a compound occurs at the temperature which changes it from a solid to a liquid, or vice versa; the boiling point of a compound occurs at the temperature which changes it from a liquid to a gas or vice versa (cost.georgiasouthern.edu). These are called phase transition points. All compounds are affected mainly by intermolecular forces which bind the molecules together; these allow the state of the compound to remain constant: solid, liquid, or gas. Depending on how strongly the atoms and molecules of the compound are attracted, the phase-transition point can be higher or lower; if the molecules of a compound are weakly attracted, it can become a gas at a lower temperature, meaning the boiling point is lower.
The reaction of the compound itself to heat and cold is also a factor. If the combined compound has a higher tolerence to heat than the separated elemental molecules, the boiling point will be higher for the compound than for the separated elements because the molecules have a stronger attraction.