Cyclopentadienyl magnesium bromide

Cyclopentadienyl magnesium bromide is a chemical compound with the molecular formula C₅H₅MgBr. The molecule consists of a magnesium atom bonded to a bromine atom and a cyclopentadienyl group, a ring of five carbons each with one hydrogen atom.

Cyclopentadienyl magnesium bromide

Skeletal formula
Identifiers
CAS Number	17306-10-4
3D model (JSmol)	Interactive image
PubChem CID	87410419
InChI InChI=1S/C5H5.BrH.Mg/c1-2-4-5-3-1;;/h1-3H,4H2;1H;/q-1;;+2/p-1 Key: MFWGSTMYJJJWEV-UHFFFAOYSA-M
SMILES C1C=CC=[C-]1.[Mg+2].[Br-]
Properties
Chemical formula	C5H5BrMg
Molar mass	169.304 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

The compound is a Grignard reagent, a type of organometallic compound that features a magnesium atom bonded to a halogen atom and to a carbon atom of some organic functional group.

This compound is of historic importance as the starting material for the first published synthesis of ferrocene by Peter Pauson and Thomas J. Kealy in 1951.^[1]

Preparation

The compound can be prepared by reacting cyclopentadiene with magnesium and bromoethane in anhydrous benzene.^[2]