 Tungsten , also known as wolfram , is a chemical element with symbol W and atomic number 74 . The word tungsten comes from the Swedish language tung sten , which directly translates to heavy stone . Its name in Swedish is volfram , however , in order to distinguish it from scheelite , which in Swedish is alternatively named tungsten . A hard gray-white metallic element, tungsten is an essential element in many alloys and is used to make filaments for light bulbs and X-ray tubes. Hinweis: Die Gleichung 2H2O + O2 = 2H2O + O2- = 2