Kemija - 2014./15. jesen - 11.

${\mathrm{C}}_4{\mathrm{H}}_4{\mathrm{N}}_2\backslash mathrm\{C\}\_\{4\}\; \backslash mathrm\{H\}\_\{4\}\; \backslash mathrm\{~N\}\_\{2\}$

${\mathrm{C}}_4{\mathrm{H}}_6{\mathrm{N}}_2\backslash mathrm\{C\}\_\{4\}\; \backslash mathrm\{H\}\_\{6\}\; \backslash mathrm\{~N\}\_\{2\}$

${\mathrm{C}}_6{\mathrm{H}}_4{\mathrm{N}}_2\backslash mathrm\{C\}\_\{6\}\; \backslash mathrm\{H\}\_\{4\}\; \backslash mathrm\{~N\}\_\{2\}$

${\mathrm{C}}_6{\mathrm{H}}_6{\mathrm{N}}_2\backslash mathrm\{C\}\_\{6\}\; \backslash mathrm\{H\}\_\{6\}\; \backslash mathrm\{~N\}\_\{2\}$