CHN Calculator

The molecular weight a formula implies and the elemental analysis it predicts — the percentages a combustion analysis is compared against.

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A chemical formula. Brackets nest and may carry a fractional multiplier (Cu(NO3)2, K3[Fe(CN)6], (SiO2)0.5), and a charge may be written after a caret (SO4^2-) or as a bare sign (Na+). The charge is noted and left out of the arithmetic: every quantity here is a sum over atoms, and an electron is one part in 10⁵ of a carbon.

Reading it

Percentages are by mass, which is how elemental analysis is reported. An unrecognised element symbol is refused rather than dropped, because dropping it would renormalise the rest and still look right.

Worked examples: aspirin · a nickel complex · copper nitrate