a particular kind or species of matter with uniform properties

a poisonous crystalline alkaloid extracted from the nightshade family; used as an antispasmodic and to dilate the eye pupil; also administered in large amounts as an antidote for organophosphate nerve agents or organophosphate insecticides

a poisonous crystalline alkaloid (isometric with atropine but more potent); used to treat excess motility of the gastrointestinal tract

a poisonous substance produced during the metabolism and growth of certain microorganisms and some higher plant and animal species

an alkane with five carbon atoms and the formula C5H12.

any of the three isomeric compounds containing a benzene ring with a methyl (CH3) and amino (NH2) group attached to it.