Sodium Borate
 
 

Above is the anhydrous structure of sodium borate.  Click on it to find an interactive 3D model of the molecule.

Often considered interchangeable with sodium borate, borax is a molecule of sodium borate with 10 water molecules attached.  Above is the structure of sodium borate as it is dissolved to create borax. Below is what sodium borate looks like in nature.




Sodium borate is considered a natural alkaline mineral, usually found deep inside the earth. In the United States, Death Valley, California, is most widely known for mining it. Sodium Borate is a crystalline white solid, sometimes found with grey, blue, or green streaks and soluble in water.  It is odorless, with a melting point of about 75ºC and a boiling point of about 320ºC.

Sodium Borate is a compound found in several slime-type children's toys and, ironically, dangerous to one's health. Exposure to sodium borate can irritate the skin, the eyes, the digestive system, and the respitory tract.  Additionally, prolonged ingestion or contact with the compound could bring about medical conditions including weight loss, vomiting, convulsions, and anemia.  A fatal dose of sodium borate is estimated to be a mere 15 to 20 grams.  At this point, you may be wondering how sodium borate could be among the ingredients for any toy, especially one that a popular children's television station douses on people for fun.  However, sodium borate is an important ingredient in Nickelodeon's Green Slime. The addition of sodium borate to polyvinyl alcohol, also present in slime, creates a "cross-linking gel," which has the recognizable characteristics of the slime.  This reaction successfully removes the harmfulness of sodium borate and creates a gooey, sticky, sloppy form of entertainment.
 
 

Here, a French chemist makes slime from borax and polyvinyl alcohol.