Borate

Borates also found use for control of weeds in specific locations. The introduction of synthetic organic herbicides that acted selectively against broad-leaved weeds changed the situation irreversibly. The first organic chemical herbicide to be introduced was 4,6-dinitro-o-cresol [534- 52-1] (DNOC) in 1932.

Borate is a salt of boric acid (H₃BO₃). There are two known types of borates - orthoborate and metaborate which are used as fertilizers. Besides these, polyborates, boric acid, calcium polyborate (colemanite), sodium tetraborate, solubor and complex borosilicate (boron frits) are also used as fertilizers to reduce boron deficiency. Borate minerals like kernite and tincal are the main sources of borax.
Borax, a source of boron, is the salt of boric acid, sodium hydroxide and sodium carbonate. Borax, otherwise called disodium tetraborate decahydrate(Na₂B₄O₇·10H₂O)is a water-soluble white compound. It occurs as a mineral in some alkaline salt deposits. The main sources of borax are borate minerals, kernite(Na₂B₄·4H₂O),a sorite and heal(Na₂B₄O₇·10H₂O)which are purified by recrystallization. On treatment with an acid, borax gives boric acid which is absorbed as boron by plants. Borax contains 10.5 to 11.4% boron or 36.5% boric oxide (B₂O₃).
Borax is a supplier of micronutrient boron for plants and is applied as such or as a foliar spray. Solubor is preferred to borax for its greater solubility and because it causes minimum changes in the crystallization temperature.
Borax is a very important substance in other industries too. It is used as a metallurgical flux in glass and ceramic industries, a buffer, a mild alkaline antiseptic and a source of boron compounds.