Precursor Stoichiometry Calculator

This is where you enter what you want to make. Type a formula below (mol% style, e.g. Ba0.8Ca0.2TiO3) and press Enter/Parse to fill the table -- or skip straight to the table below and enter rows by hand (needed for Wt% mode, since a plain formula string can't carry molar-mass info).

Table view (always the source of truth when you hit Solve). One row per element. In Mol% mode "Concentration" is the element's stoichiometric coefficient. In Wt% mode it's the element's weight fraction/percent, and "Molar mass" converts it to mole ratios. Include every element physically in the target compound here, even one you'll mark DO-NOT-balance below (e.g. oxygen): that flag only removes it from the precursor-balance equations, it doesn't remove its mass from the target, so leaving its concentration at 0 will throw off the total target molar mass.

Solve several full compositions at once, e.g. different doping levels of the same system, instead of one at a time. List each composition as a mol% formula (same convention as the quick-entry field above), one per line. Every composition must use exactly the same elements (and therefore the same precursors below), that's what makes one balance solve reusable across the whole batch; results are shown one row per composition, headed by its formula.

Enter each precursor as a chemical formula, e.g. BaCO3, TiO2, Ca(NO3)2, SrCO3, start typing for suggestions from a library of common reagents. Molar mass is computed automatically.

One rule per line. A bare element (e.g. O) drops it from every balance equation (assumed freely available, e.g. atmospheric oxygen). A group rule GROUP=REPLACEMENT treats that group as decomposing to the replacement for balance purposes only, e.g. CO3=O treats a carbonate group as leaving 1 O behind (releasing CO2); NO3=O likewise for nitrate; H2O= (empty replacement) drops crystal water entirely from the balance while still counting its mass in the precursor's molar mass.