Boron (B) is a naturally occurring dark brown/black substance found throughout the environment. It only occurs in combined form, usually as borax, colemanite (Ca2B6O11-5H2O), boronatrocalcite (CaB4O7NaBO2-8H2O) and boracite (Mg7Cl2B16O30) (Eisler, 1990). It belongs to Group 13 on the periodic table and has properties which are borderline between metals and non-metals. It is a semiconductor rather than a metallic conductor and it is more related chemically to silicon than to aluminium, gallium, indium, or thallium (Winter, 1998). Its atomic weight is 10.811 and is in its solid state at 298?K. Boron?s melting point is 2349?K and boiling point is 4200?K.
Moss, S.A.; Nagpal, N.K.. 1981. Ambient Water Quality Guidelines for Boron