Contoh:

judul artikel penulisan asli pemakaian yang benar salah hasil
H2O H2O {{downsize|H<sub>2</sub>O}} {{downsize|<span style="color: red">H<sub>2</sub>O</span>}}
Reaksi SN1 Reaksi SN1 {{downsize|Reaksi S<sub>N</sub>1}}

Never use anything other than the exact pagetitle combined with <sub></sub> and <sup></sup>-tags.