Life could not exist without sodium compounds. These compounds retain water in body tissues, and severe sodium deficiency can lead to death. Blood contains sodium compounds in solution. Sodium compounds are used industrially in chemical and pharmaceutical manufacturing, in metallurgy, in sodium vapor lamps, and in the production of hundreds of everyday products. One of the most common sodium compounds is table salt, or sodium chloride. In its pure form, sodium is a silvery-white, soft, waxy metallic element. It is the sixth most abundant element on Earth and is found in greater quantities than trace amounts in the stars and sun. The secret that led to low-cost production was discovered in 1789, when French chemist Nicolas Leblanc discovered how to make soda from common salt. The compound called soda is sodium carbonate. Raw sodium carbonate is called sodium carbonate. Carbonate also combines with water in the form of crystals known as washing soda or sal soda. Soda is used in the manufacture of soap, glass, dyes and explosives and as a base for making other sodium compounds. Other sodium compounds, with some of their uses, are: baking soda (sodium bicarbonate), an ingredient in baking powder; borax (sodium borate), a food preservative; and caustic soda, or lye (sodium hydroxide), used in soap making. Some properties of sodium are: symbol Na, atomic number 11, atomic weight 22.9898, boiling point 1621.2 F, and melting point 208.06 F. Sodium belongs to the group of elements called alkali metals. It is never found in its raw state and was first isolated by English scientist Sir Humphry Davy in 1807. Lighter than water, pure sodium can be cut with a knife at room temperature and is brittle at low temperature. It conducts heat and electricity easily and exhibits a photoelectric effect, that is, it destroys its electrons when exposed to light. In its pure form, sodium oxidizes