Tungsten Tungsten Tungsten, or wolfram, is a chemical element with symbol W and atomic number 74. The name "tungsten" comes from the former Swedish name for the tungstate mineral "scheelite", "tung sten" or "heavy stone". Tungsten is a rare metal found naturally on Earth almost exclusively combined with other elements in chemical compounds rather than alone. It was identified as a new element in 1781 and first isolated as a metal in 1783. Its important ores include wolframite and scheelite. The free element is remarkable for its robustness, especially the fact that it has the highest melting point of all the
Neptunium of manganese. Neptunium metal is similar to uranium in terms of physical workability. When exposed to air at normal temperatures, it forms a thin oxide layer. This reaction proceeds more rapidly as the temperature increases. Neptunium has been determined to melt at 639±3 °C: this low melting point, a property the metal shares with the neighboring element plutonium (which has melting point 639.4 °C), is due to the hybridization of the 5f and 6d orbitals and the formation of directional bonds in the metal. The boiling point of neptunium is not empirically known and the usually given value of 4174