Question

What is Beta-Black phosphorus?

Answer 1

Hint: We know that in nature, there are different allotropic forms of phosphorus. The most important allotropic forms are- white Phosphorus, red phosphorus and black phosphorus. Due to the high reactivity, phosphorus is not found free in nature.

Complete answer: Black Phosphorus exists in two different forms- beta-black Phosphorus and beta-black Phosphorus. Here, we are going to discuss more about bet-Phosphorus. Beta-Phosphorus is formed when white Phosphorus is heated at $473K$ under $4000-1200$ atmospheric pressure. Black Phosphorus consists of a double-layered crystal lattice and has zig-zag chains between $P-P-P$ bonds. It has a bond angle of $99$ degrees and a bond length of $218Pm$.
Black beta phosphorus is an allotrope of phosphorus consisting of multiple layers with two-dimensional structures, weakly bonded to one another by van der Waals forces. When separated, the resulting monolayer material is known as phosphorene. Beta black phosphorus is formed when red phosphorus is heated in a sealed tube at . It can be sublimed in air and has opaque monoclinic or rhombohedral crystals. It does not oxidize in air.

Additional Information:
There are various physical and chemical properties of black Phosphorus which are discussed below. Physical properties of black Phosphorus: Black Phosphorus is black in colour and exists in both crystalline and amorphous forms. It has a melting point of $860K$ and has a specific gravity of $2.69$. Chemical properties of black Phosphorus: Black phosphorus is the most stable and least reactive among all other allotropes of Phosphorus and therefore it does not show any reactivity among oxygen, halogens, sulfur etc. Phosphorus is an essential element to life since it forms a major part in DNA, RNA and membranes. It is also present in the molecules responsible for energy generation such as ADP, ATP.

Note:
Remember that Black beta phosphorus is the least reactive form of phosphorus and has no significant commercial uses. The latest addition to the family of layered materials, has attracted much interest owing to potential optoelectronics, Nano electronics, and biomedicine applications. Little is known about its toxicity, such as whether it could be as toxic as white phosphorus.