<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Black As<sub>x</sub>P<sub>1‐x</sub> (x = 0, 0.25, 0, 4) is prepared by vapor transport of a mixture of gray As and red P to which a Sn/SnCl<sub>4</sub> mixture is given as mineralizer (evacuated silica tubes, complex heating and cooling schedules) and subsequently exfoliated for optical and electrochemical measurements.</p> </abstract>