Cyclopentadienyltungsten(II) tricarbonyl hydride

Synonym: Tricarbonyl(cyclopentadienyl)hydridotungsten(II), CpWH(CO)3

CAS Number 12128-26-6 


Product codeW8266
CAS number12128-26-6
Assay (purity)98%+
Purity methodby elemental analysis: %C=28.2-29.3; %H=1.8-1.9
Molecular weight333.97 g/mol
Melting point69 °C (156 °F)
Appearancewhite to yellow to orange to beige powder or crystals
Molecular formulaC8H6O3W
Linear formulaC8H6O3W
Storage temperature2 – 8 °C(35.6 – 46.4 °F)
Packagingglassware/metal containers/bubblers

Cyclopentadienyltungsten(II) tricarbonyl hydride has been used as a tungsten hydride model complex with covalently attached pyridyl groups as proton acceptors. Metal hydrides are key intermediates in catalytic proton reduction and dihydrogen oxidation. There is currently much interest in appending proton relays near the metal center to accelerate catalysis by proton-coupled electron transfer (PCET). Such knowledge is crucial for rational improvements of solar fuels catalysts. See links below

Ereztech manufactures and sells this product in small and bulk volumes. Glass ampules, bottles or metal ampules or bubblers are available for packaging. For additional analytical information or details about purchasing W8266 contact us at

Safety information

Hazardous class4.3(4.1)
Packing groupIII
PictogramsGHS02 GHS07
Signal wordDANGER
Hazard statementsH228-H261-H315-H319-H335
Precautionary statementsP210-P223-P231 + P232-P240-P241-P261-P264-P271-P280-P302 + P352-P304 + P340-P305 + P351 + P338-P312-P334 + P335-P337 + P313-P362-P370 + P378
Transport descriptionOrganometallic substance, solid, water-reactive, flammable (Cyclopentadienyltungs ten(II) tricarbonyl hydride)
In TSCA registryNo (research and development usage only)

First Aid Measures

General adviceConsult a physician. Show this safety data sheet to the doctor in attendance. Move out of the dangerous area.
Eye contactRinse thoroughly with plenty of water for at least 15 minutes and consult a physician.
Skin contactWash off with soap and plenty of water. Consult a physician.
InhalationIf breathed in, move person into the fresh air. If not breathing, give artificial respiration. Consult a physician.
If swallowedDo NOT induce vomiting. Never give anything by mouth to an unconscious person. Rinse mouth with water. Consult a physician.


Certificates of Analysis (CoA)

If you don’t see the needed lot of Cyclopentadienyltungsten(II) tricarbonyl hydride below please contact customer support at

Lot# 006/542

External identifiers for CpWH(CO)3

Pubchem CID59211708
IUPAC Name3a,4,7,7a-tetrahydro-2-benzofuran-4,7-diide-1,3-dione;tungsten(2+)
InchI IdentifierInChI=1S/C8H6O3.W/c9-7-5-3-1-2-4-6(5)8(10)11-7;/h1-6H;/q-2;+2

Known applications and external links

With Cyclopentadienyltungsten(II) tricarbonyl hydride other customers often ask:

Ereztech synthesizes and sells additional W-compounds.

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