====== Silicate Earth composition based on CI Carbonaccous Chondrites (compounds) ====== Source: McDonough W.F., Sun S.-s. The composition of the Earth, Chemical Geology 120 (1995) 223-253. oxide;units;value SiO2;pt;45.16 TiO2;pt;0.217 Al2O3;pt;3.97 Cr2O3;pt;0.46 MnO;pt;0.13 FeO;pt;7.82 NiO;pt;0.27 MgO;pt;38.3 CaO;pt;3.5 Na2O;pt;0.33 K2O;pt;0.031