Molybenum (pronounced /məˈlɪbdənəm/, from the Greek meaning "lead-like"), is a Group 6 chemical element with the symbol Mo and atomic number 42. It has the sixth-highest melting point of any element, and for this reason it is often used in high-strength steel alloys. Molybdenum is found in trace amounts in plants and animals, although excess molybdenum can be toxic in some animals. Molybdenum was discovered in 1778 by Carl Wilhelm Scheele and first isolated in 1781 by Peter Jacob Hjelm.