Arsenic
Occurrence, isolation & synthesis
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Steel-gray, shiny brittle metal in α-form, dark grey in β-form [7]. OccurrenceIn nature, arsenic is found in the Earth's crust, 1.8 ppm, in minor quantities as elemental arsenic and in minerals such as realgar, orpiment, and arsenolite [7]. The isotope found in nature is 75As (100 %, stable) [7].
In pure solid form, arsenic exist in the following forms: α-form: rhombohedral crystal at > 280 °C [7] β-form: amorphous structure at < 280 °C [7] |