sentence: Yellow arsenic is unstable and rare.
sentences_before: Arsenic is found in three allotropes. Gray arsenic is the most common. It is a brittle, somewhat soft metalloid that is a little shiny. It is a semiconductor.
sentences_after: It is the most toxic allotrope. It is a soft and waxy nonmetal, similar to white phosphorus. It turns into gray arsenic in light. Black arsenic is similar to red phosphorus. It is a brittle, black, and shiny nonmetal.
concept_name: yellow arsenic
headings: Arsenic Properties Physical properties
categories: Semimetals Chemical elements