Iron, a metal, is the 26th element on the periodic table. Its atomic weight is 55.845, and it exists as a solid at room temperature. Iron melts at 2,800 degrees Fahrenheit and boils at 5,182 F. In its pure state, iron has a density of 7.874 grams per cubic centimeter.
Iron is one of the most abundant metals on Earth, comprising 5.6 percent of the crust. Iron alloys with carbon to make steel, and it is easily alloyed with many other metals, such as tungsten and chromium. Iron is essential to both photosynthesis and respiration because of its affinity for oxygen.