The conversation between human and AI assistant.
Why is [math]\mathrm{Cr}^{6+}[/math] (hexavalent chromium) more toxic than [math]\mathrm{Cr}^{3+}[/math] (trivalent chromium)?
I see. And why does [math]\mathrm{Cr}^{6+}[/math] interact more easily with biological molecules than [math]\mathrm{Cr}^{3+}[/math]?
This is because [math]\mathrm{Cr}^{6+}[/math] has a higher charge and a smaller size than [math]\mathrm{Cr}^{3+}[/math], which allows it to more easily bind to biological molecules and disrupt their structure and function.