Melting point of ice at 1 atmosphere of pressure is very close to ; this is also known as the ice point. In the presence of nucleating substances, the freezing point of water is not always the same as the melting point. In the absence of nucleators water can exist as a supercooled liquid down to −48.3 °C (−55 °F, 224.8 K) before freezing. The chemical element with the highest melting point is tungsten, at ; this property makes tungsten excellent for use as filaments in light bulbs. The often-cited carbon does not melt at ambient pressure but sublimes at about ;
Period 3 element chloride for use as a deicing agent and a nutrient. The free metal, elemental sodium, does not occur in nature but must be prepared from sodium compounds. Elemental sodium was first isolated by Humphry Davy in 1807 by the electrolysis of sodium hydroxide. The same ion is also a component of many minerals, such as sodium nitrate. "Magnesium" (symbol Mg) is an alkaline earth metal and has common oxidation number +2. It is the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole. Magnesium is the fourth most common element in the