Kemija - 2014./15. ljeto - 20.

${\mathrm{H}}_2\backslash mathrm\{H\}\_\{2\}$

${\mathrm{H}}_3{\mathrm{O}}^{+}\backslash mathrm\{H\}\_\{3\}\; \backslash mathrm\{O\}^\{+\}$

${\mathrm{O}}_2\backslash mathrm\{O\}\_\{2\}$

${\mathrm{H}}^{-}\backslash mathrm\{H\}^\{-\}$