a. Arsenic trioxide (As2O3) and Arsenic trisulfide (As2S3)
b. As2O3 As2S3
c. Arsenic sulfides and oxides have been known since ancient times. The element was first isolated by Albertus Magnus in 1250.
d. Arsenic trioxide: Large scale applications include its use as a precursor to forestry products, in colorless glass production, and in electronics.
Arsenic trisulfide: As orpiment. The ancient Egyptians reportedly used orpiment, natural or synthetic, as a pigment in artistry and cosmetics.
e. Arsenic trioxide: As the symptoms of arsenic poisoning were somewhat ill-defined, it was frequently used for murder until the advent of the Marsh test, a sensitive chemical test for its presence. (Another less sensitive but more general test is the Reinsch test.) Owing to its use by the ruling class to murder one another and its potency and discreteness, arsenic has been called the “poison of kings” and the “king of poisons”.
Arsenic trisulfide: The ancient Egyptians reportedly used orpiment, natural or synthetic, as a pigment in artistry and cosmetics.