Group 13 elements – occurrence
Boron is a fairly rare element and it occurs to a very small extent around 0.0001% by mass in earth’s crust. It is a very light element. It occurs in two allotropic forms, 10B(19%) 11B(81%). It does not occur in free-state but occurs as borates and orthoboric acid. The main ores of boron are:
The deposits of boron are found in California, Turkey, Argentina, China, Bolivia, and Peru. In Turkey, around 70% of world’s boron is extracted. In India, boron occurs as borax in Puga Valley of Ladakh region in Kashmir and also in Sambhar lake of Rajasthan.
Among the elements of group 13, aluminium is the most abundant element in eath’s crust after oxygen and silicon. It is present about 8.3% by mass in earth’s crust. It is unlike boron, it is uncommon in nature as free-state, it is because of its tendency to attract oxygen atoms and forming several aluminium oxides. It is a major constituent of many aluminisilicate rocks such as feldspars and micas. In India, aluminium is found as mica in Madhya Pradesh, Karnataka, Orissa, and Jammu. Aluminium is found in countries like Ghana, Surinam, Russia, Indonesia, Brazil, and Australia. The important minerals of aluminium are:
Bauxite is commercially the most important ore from which aluminium metal is extracted.
Gallium, Indium, and Thallium are very much less abundant and occur in the traces in sulphide minerals rather than oxides. Small amount of gallium are also found in the ores of elements adjacent to it in the periodic table (Al, Zn, Ge). It has been found in the trace amount in a variety of ores, including bauxite and sphalerite, and also in minerals such as germanite and diaspore. Highest concentration of gallium is found in the ore called germanite which is a complex sulphide of Zn, Cu, Ge, and As. Trace amount of gallium has also been found in coals.
Indium is also a rare element in boron family. It is even less abundant than gallium present only about 0.05ppm in earth’s crust. It is the 61st most common element in earth’s crust. Minerals of indium are very scarce, one of them is indie. Indium can also be found in several zinc ores, also in some copper and lead ores, but in very minute quantities. Canada has the most amount of indium reserve but United states and China also have moderate reserve. Thallium occurs in earth’s crust in the abundance of around 0.6 ppm. It is the 56th most common element in earth’s crust. It is found in some ground, soil, rocks, clay, etc. it is also found in the many sulfide ores of Zn, Fe, and Co. in minerals like crookesite, routhierite,bukovite, hutchinsonatie, and sabatierite. Traces of Indium and Thallium are found in ZnS and PbS.
Nihonium is the element never found in nature, but it is synthesized in a laboratory. Thus, it is called a synthetic element.
The abundance of group 13 elements in the earth’s crust is shown below:
|Element||Abundance in earth’s crust (ppm)||Relative abundance|