The Tebbe reagent is the organometallic compound with the formula (C5H5)2TiCH2ClAl(CH3)2. It used in the methylenation of carbonyl compounds, that is it converts organic compounds containing the R2C=O group into the related R2C=CH2 derivative. It is a red solid that is pyrophoric in the air, and thus is typically handled with air-free techniques. Tebbe's reagent contains two tetrahedral centers linked by a pair of bridging ligands. Titanium features two cyclopentadienyl ([C5H5] , or Cp) rings, and aluminium features two methyl ligands. The titanium and aluminium atoms are bridged by both CH2 and chloride ligands.