Calcium hydroxide
Calcium hydroxide (traditionally called slaked lime) is an inorganic compound with the chemical formula Ca(OH). It is a colorless crystal or white powder and is obtained when calcium oxide (called "lime" or "quicklime") is mixed, or slaked with water. It has many names including hydrated lime, caustic lime, builders' lime, slack lime, cal, or pickling lime. Calcium hydroxide is used in many applications, including food preparation, where it has been identified as E number E526. Limewater is the common name for a saturated solution of calcium hydroxide.
Hydrotalcite
Hydrotalcite is a layered double hydroxide of general formula 
·), whose name is derived from its resemblance with talc and its high water content. The layers of the structure stack in multiple ways, to produce a 3-layer rhombohedral structure (3"R" Polytype), or a 2-layer hexagonal structure (2"H" polytype) formerly known as manasseite. The two polytypes are often intergrown. The carbonate anions that lie between the structural layers are weakly bound, so hydrotalcite has anion exchange capabilities.