= Crystal violet cation
The \b[<crystal violet cation>] is the positively charged organic component of the <crystal violet> salt. Its <molecular formula> is $\mathrm{C_{25}H_{30}N_3^+}$, with net charge $+1$. The complete chloride salt additionally contains a chloride <counterion>; the isolated organic <cation> does not contain a chlorine atom.<Crystal violet in ChEBI>[CHEBI:41688, has-part relation; CHEBI:77181, cation formula, charge and structure]{ref}
The <cation> contains three substituted aromatic rings and nitrogen-containing groups in a <conjugated system>. A drawn charged <Lewis structure> is a representation of that electronic system, rather than a claim that the molecular charge is a classical point permanently confined to the atom carrying the printed plus sign. <Resonance (chemistry)> distinguishes alternative electronic representations from different chemical substances.
An original mass check uses the ChEBI average masses $372.536\,\mathrm{g\,mol^{-1}}$ for the <cation> and $407.989\,\mathrm{g\,mol^{-1}}$ for the chloride formula unit. Their difference, $35.453\,\mathrm{g\,mol^{-1}}$, is the chloride contribution under that atomic-mass convention. For $1.00\,\mathrm{mmol}$ of ideal anhydrous salt, the sample contains $1.00\,\mathrm{mmol}$ of dye <cations> and $1.00\,\mathrm{mmol}$ of chloride <ions>; the total sample mass is $407.989\,\mathrm{mg}$, not $372.536\,\mathrm{mg}$.
The organic <cation> accounts for about $372.536/407.989\simeq91.31\%$ of that ideal salt's mass. Confusing the two <molar masses> therefore changes an amount calculation even when the desired number of dye <ions> is specified correctly. This stoichiometric distinction does not itself predict dye binding, solution speciation or the <crystal violet biomass response>.
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