NH3\mathrm{NH}_{3}NH3
C6H5−NH2\mathrm{C}_{6} \mathrm{H}_{5}-\mathrm{NH}_{2}C6H5−NH2
(C6H5)2NH\left(\mathrm{C}_{6} \mathrm{H}_{5}\right)_{2} \mathrm{NH}(C6H5)2NH
(C6H5)3 N\left(\mathrm{C}_{6} \mathrm{H}_{5}\right)_{3} \mathrm{~N}(C6H5)3 N