Cal. Rev. & Tax. Code § 47015

For purposes of this part, the lithium and lithium compounds extracted shall be converted to lithium carbonate equivalent by multiplying the tonnage of lithium and lithium compounds by the appropriate conversion factor, as follows:Lithium or lithium compound:Conversion factor:Lithium (Li)5.323Lithium oxide (Li2O)2.473Lithium chloride (LiCl)0.871Lithium bromide (LiBr)0.425Lithium hydroxide monohydrate (LiOH.H2O)0.880Butyllithium (C4HgLi)0.576Lithium carbonate (Li2CO3)1.000