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Arsenic is a chemical element with the symbol As and the atomic number 33. It is a metalloid and one of the pnictogens , and therefore shares many properties with its group 15 neighbors phosphorus and antimony .
Alchemical symbols were used to denote chemical elements and compounds, as well as alchemical apparatus and processes, until the 18th century. Although notation was partly standardized, style and symbol varied between alchemists.
Alchemical Symbols is a Unicode block containing symbols for chemicals and substances used in ancient and medieval alchemy texts. Many of the symbols are duplicates or redundant with previous characters. [3] Few fonts support more than a few characters in this block as of 2021. One that does and is free for personal use is Symbola 14.0.
Chemical symbols are the abbreviations used in chemistry, mainly for chemical elements; but also for functional groups, chemical compounds, and other entities. Element symbols for chemical elements, also known as atomic symbols , normally consist of one or two letters from the Latin alphabet and are written with the first letter capitalised.
The Russell-Saunders term symbol of the ground state in all elements in the group is 4 S 3 ⁄ 2. The most important elements of this group to life on Earth are nitrogen (N), which in its diatomic form is the principal component of air, and phosphorus (P), which, like nitrogen, is essential to all known forms of life.
Arsenic is used as the group 15 element in the III-V semiconductors gallium arsenide, indium arsenide, and aluminium arsenide. [10] The valence electron count of GaAs is the same as a pair of Si atoms, but the band structure is completely different which results in distinct bulk properties. [11]
The group 1 alkali metals and the group 2, alkaline earth metals, form arsenides with isolated arsenic atoms. They form upon heating arsenic powder with excess sodium gives sodium arsenide (Na 3 As). The structure of Na 3 As is complex with unusually short Na–Na distances of 328–330 pm which are shorter than in sodium metal.
Arsenic and antimony compounds are especially toxic; boron, silicon, and possibly arsenic, are essential trace elements. Boron, silicon, arsenic, and antimony have medical applications, and germanium and tellurium are thought to have potential. Boron is used in insecticides [121] and herbicides. [122] It is an essential trace element. [123]