From which type of phosphorus is alpha -black phosphorus formed?

From which type of phosphorus is alpha -black phosphorus formed? Correct Answer Red phosphorus

Alpha-black phosphorus is the most stable allotrope of black phosphorus. Alpha-black phosphorus is produced from red phosphorus. When red phosphorus is heated in a sealed tube at 803 K, it forms alpha-black phosphorus.

Related Questions

A system in a normalized state $$\left| \psi \right\rangle = {c_1}\left| {{\alpha _1}} \right\rangle + {c_2}\left| {{\alpha _2}} \right\rangle $$    with $$\left| {{\alpha _1}} \right\rangle $$ and $$\left| {{\alpha _2}} \right\rangle $$ representing two different eigen states of the system requires that the constants c1 and c2 must satisfy the condition