Ratio of Disproportionation to Combination of N2H3 Radicals

The hydrazyl radical (N₂H₃) has been generated in the absence of direct decomposition of hydrazine by the reaction H+H₂H₄→N₂+H₂H₃. Photolysis of CH₃SH at 2537 Å was used as a source of atomic hydrogen. Using various mixtures of ²⁸N₂H₄ and ³⁰N₂H₄, the distribution of isotopic nitrogens formed in this system leads to ${(}^{29}{\mathrm{N}}_2{)}^2{\mathrm{\hspace{0.17em}/\hspace{0.17em}(}}^{28}{N}_2{\mathrm{)(}}^{30}{\mathrm{N}}_2{\text{)\hspace{0.17em}=\hspace{0.17em}1.3\hspace{0.17em}×\hspace{0.17em}10}}^{\text{−2}}$ . Identifying radomization of isotopic nitrogen with combination N₂H₃ and nonradomization with disproportionation of N₂H₃, the ratio of disproportionation to combination is approximately 4. This is an unexpectedly large value, being nearly 30 times larger than that for the analogous hydrocarbon radical C₂H₅.