Black arsenic: Fact or fiction? Synthesis and identification of metastable compounds
Friday, February 17, 2012 - 09:30
in Physics & Chemistry
(PhysOrg.com) -- Phosphorus and arsenic are on top of each other in one group of the periodic table, so they have many similar properties. In addition to tubular forms, phosphorus is found in white, red, black, and purple structural forms. At room temperature, black phosphorus is the stable form; the others are metastable. According to textbooks, arsenic occurs in gray, yellow, and black forms. However, the existence of black arsenic, which should be analogous to black phosphorus, has never been indisputably proven. In the journal Angewandte Chemie, German researchers have now demonstrated that black arsenic is metastable in its pure form, and that it has thus far only been obtained in a form stabilized by atoms of other elements.