Calcium oxide15 is known as lime1116 and is one of the top 10 chemicals1217 produced annually by thermal decomposition of limestone. The thermal decomposition of calcium carbonate to lime18 is one of the oldest chemical reactions known. For several thousand years, lime has been used in mortar (a paste of lime, sand and water) to cement stones to one another in buildings, walls and roads. The setting of mortar involves several chemical reactions.
1 Congregation Shearith Israel, 1654, Upper West Side, Manhattan, is the oldest congregation in New York and the United States. 2  Temple Society of Concord, 1839, Syracuse, New York.  Angel Orensanz Center, 1849, Lower East Side, Manhattan, is the oldest synagogue building still standing in New York State.
May 28, 1967. The Old Stone House is the oldest unchanged building in Washington, D.C., United States. The house is also Washington's last Pre-Revolutionary Colonial building on its original foundation. Built in 1765, Old Stone House is located at 3051 M Street, Northwest in the Georgetown neighborhood. Unlike many Colonial homes in the area, sentimental local folklore preserved the Old Stone House from being demolished.