What molecule am I?


Fipronil is a broad-spectrum insecticide. It disrupts insects鈥� central nervous systems by blocking chloride channels that are gated by 纬-aminobutyric acid (GABA) or glutamate. These receptors are weaker or nonexistent in mammals.
Fipronil has a chiral center at the sulfur atom in the sulfoxide group; the two enantiomers have been isolated and verified. The article of commerce is a racemic mixture of the two.
Fipronil formulations sold worldwide include flea-control products for pets, cockroach traps, and insecticides for agrciultural crops, lawns, golf courses, and the like. But despite its wide range of uses and relative harmlessness toward mammals, fipronil is a significant environmental hazard. It is highly toxic to fish and other waterborne wildlife, birds, and beneficial insects. It has been cited as one of the primary causes of .
In 2017, fipronil was the culprit in a food-contamination scandal in the Netherlands. Molecule of the Week鈥檚 Dutch reader who suggested this molecule provided this narrative:
- Egg-laying chickens in the Netherlands are plagued by red mites (bloodmites, Dermanyssus gallinae), which cause anemia and reduce egg output.
- To combat these mites, farmers turned to a tiny company in the Netherlands called Chickfriend. The company offered an effective way to exterminate the mites by fumigation.
- Chickfriend helped hundreds of chicken farmers get rid of the mites for months.
- But鈥攊t turned out that Chickfriend鈥檚 fumigant contained fipronil, which was banned in the Netherlands. Contamination of Dutch eggs, which are sold worldwide, plunged the industry into a tailspin, with estimated damages running into the hundreds of millions of euros.
A in the Dutch newspaper De Stentor chronicles the fipronil scandal, including the subsequent legal fallout and a better way to combat red mites. (Note: The article is in Dutch, but it is easily translated by major Web browsers.)
Fipronil hazard information
Hazard class* | Hazard statement | |
---|---|---|
Acute toxicity, oral, category 3 | H301鈥擳oxic if swallowed | ![]() |
Acute toxicity, dermal, category 3 | H311鈥擳oxic in contact with skin | ![]() |
Serious eye damage/eye irritation, category 2A | H319鈥擟auses serious eye irritation | ![]() |
Acute toxicity, inhalation, category 3 | H331鈥擳oxic if inhaled | ![]() |
Specific target organ toxicity, repeated exposure, oral, category 1 | H372鈥擟auses damage to organs through prolonged or repeated exposure if swallowed | ![]() |
Short-term (acute) aquatic hazard, category 1 | H400鈥擵ery toxic to aquatic life | ![]() |
Long-term (chronic) aquatic hazard, category 1 | H410鈥擵ery toxic to aquatic life with long-lasting effects | ![]() |
*Globally Harmonized System of Classification and Labeling of Chemicals.聽聽
This molecule was suggested by a reader. We present聽almost all of the molecules suggested by our readers.聽If you have a molecule you would like us to consider, please send us a message. And thank you for your interest in Molecule of the Week! 鈥擡d.
贵颈辫谤辞苍颈濒听fast facts
CAS Reg. No. | 120068-37-3 |
nomenclature | 1H-Pyrazole-3-carbonitrile, 5-amino-1-[2,6-dichloro-4-(trifluoromethyl) phenyl]-4-[(trifluoromethyl) sulfinyl]- |
Empirical formula | C12H4Cl2F6N4OS |
Molar mass | 437.15 g/mol |
Appearance | White to yellow powder |
Melting point | 200.5 潞C |
Water solubility | 2 mg/L |
MOTW update:
April 24, 2023
Fipronil1聽is a broad-spectrum insecticide with several known environmental hazards, including contamination of chicken eggs in the Netherlands in 2017. Earlier this month, Weidong Qu and colleagues at Fudan University (Shanghai), the China National Center for Food Safety Risk Assessment (Beijing), Qingdao University (China), and Oxford University (UK) reported that fipronil and its metabolites in drinking water can produce .
1. CAS Reg. No. 120068-37-3.

, the most authoritative and comprehensive source for chemical information.
Molecule of the Week needs your suggestions!
If your favorite molecule is not in our聽archive, please send us a message. The molecule can be notable for its current or historical importance or for any quirky reason. Thank you!
Stay Ahead of the Chemistry Curve
Learn how ACS can help you stay ahead in the world of chemistry.