# Carbonate and Oxide Elements Conversion Table

When weight based analytical results need to be converted, use the table bellow. For example 56.0% CaO might be obtained during a microprobe calcite analysis. To convert this oxide to carbonate look at the table below. Find the conversion for CaCO3 to CaO and use the multiplying factor beside CaCO3. The result is 56 x 1.7848 = 99.94% CaCO3.

A factor is the sum of the atomic weights of the elements in the required formula divided by the sum of the atomic weights in the original formula. For example the factor to convert Fe2O3 to 2FeO is 2 x (55.85 + 16)/(55.85 x 2 + 16 x 3) = 0.8998 while the factor to convert 2FeO to Fe2O3 is 1/0.8998 = 1.1113.

 Divide by Oxide Element Multiply 2.1395 SiO2 Si 0.4674 1.6681 TIO2 Ti 0.5995 1.8893 Al2O3 2Al 0.5293 1.4298 Fe2O3 2Fe 0.6994 1.2865 FeO Fe 0.7773 1.1113 Fe2O3 2FeO 0.8998 1.2912 MnO Mn 0.7745 1.3883 Mn3O4 3Mn 0.7203 1.5825 MnO2 Mn 0.6319 1.6581 MgO Mg 0.6031 1.3992 CaO Ca 0.7147 2.4973 CaCO3 Ca 0.4004 1.7848 CaCO3 CaO 0.5603 1.3479 Na2O 2Na 0.7419 2.3052 Na2CO3 2Na 0.4338 1.7101 Na2CO3 Na2O 0.5848 1.2045 K2O 2K 0.8302 1.7674 K2CO3 2K 0.5658 1.4672 K2CO3 K2O 0.6816 2.2915 P2O5 2P 0.4364