Kemija - 2012./13. ljeto - 27.

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

${\mathrm{N}\mathrm{H}}_3\backslash mathrm\{NH\}\_\{3\}$

${\mathrm{N}\mathrm{O}}_2\backslash mathrm\{NO\}\_\{2\}$

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