This category of compound is the name given to a wide variety of oxyanions that are boron-containing. It is also used to refer to tetrahedral boron anions, or any chemical compound partially comprised of borate anions. Borates are naturally occurring in both mineral and borosilicate form. Borates are often derived from the salts of boric acid. Borosilicate glass, better known as pyrex, is one of the best known uses for borates in commercial manufacturing. Borosilicates are ideal for forming glass with a low coefficient thermal expansion, which is significantly more resistant to cracking at high temperatures compared to traditional soda glass. The second most commonly used borates are sodium metaborate and borax. Borax tends to only form large deposits in extremely arid climes since it is soluble in water, so the largest deposits are usually located in desert country. Borax is not only used in cleaning solution, but also as a low cost means of pest control.