Arsenic is a chemical element, having the chemical symbol As. Its atomic number (the number of protons) is 33. It has a standard atomic weight of 74.9216 g•mol −1 and is a solid in its elemental form.
Arsenic is considered to be a member of the "Metalloid" class of element. At a pressure of 1 atm (101.325 kPa), it has a sublimation point of 613 °C and, at a pressure of 28 atm, it has a melting point of 817 °C.
- Note: If the boiling point was also measured at a pressure of 28 atm, it would be higher than the melting point.