Chloroxynil

Chloroxynil
Names
	Preferred IUPAC name 3,5-dichloro-4-hydroxybenzonitrile
Identifiers
CAS Number	1891-95-8;
3D model (JSmol)	Interactive image;
EC Number	217-572-4;
PubChem CID	74685;
UNII	GI6X21WSVN;
	InChI InChI=1S/C7H3Cl2NO/c8-5-1-4(3-10)2-6(9)7(5)11/h1-2,11H Key: YRSSHOVRSMQULE-UHFFFAOYSA-N;
	SMILES C1=C(C=C(C(=C1Cl)O)Cl)C#N;
Properties
Chemical formula	C7H3Cl2NO
Molar mass	188.01 g·mol−1
Appearance	Off-white solid
Melting point	140 °C (284 °F; 413 K)
Solubility in water	Slightly soluble
Hazards
	Occupational safety and health (OHS/OSH):
Main hazards	Toxic, harmful to aquatic life, irritant
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H301, H311, H315, H319, H331, H335
	Lethal dose or concentration (LD, LC):
LD50 (median dose)	200 mg/kg (oral, rat)
LC50 (median concentration)	21.4-27.5mg/L (96h, Pimephales promelas)
Related compounds
Related compounds	Ioxynil, Bromoxynil, Bromoxynil octanoate
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Chloroxynil is a postemergent benzonitrile herbicide, used to control broad leaved weeds on cereal crops. It was manufactured by Rhone-Poulenc and May & Baker, and is now considered obsolete, though its usage may continue.

Chloroxynil was developed as a variant of bromoxynil, which is identical except for bromines replacing chloroxynil's chlorines. A 1972 study found chloroxynil less injurious to alfalfa and red clover, but also less potent at controlling broadleaf weeds.

Chloroxynil's MoA inhibits electron transfer in the photosystem II receptor. Its HRAC group is Group C, (Australia) C3 (global) or 6 (numeric).