Molybdenum is a chemical element with the symbol Mo and atomic number 42. This silver-coloured metal has the sixth highest melting point of all metals. Molybdenum’s ability to withstand high temperatures without expanding or softening makes it useful in high-pressure and high-temperature applications. The electrical and thermal conductivity for molybdenum is about one-third that of copper. Chemically speaking, molybdenum is not very reactive. It is resistant to water and air at normal temperature.