👉 Selenotropy, also known as selenide or selenic acid, is a chemical element with atomic number 20. It has the symbol Se and is an allotrope of sulfur. Selenite is a mineral that contains the element in its naturally occurring form. Selenotropy refers to the phenomenon where a substance exhibits different physical properties depending on the concentration of its constituent elements, such as the amount of selenide present or the presence of other elements like oxygen
