Pentazolate Explained

In chemistry, a pentazolate is a compound that contains a cyclo-N₅⁻ ion, the anion of pentazole. In 2017, researchers prepared the first salt (N₅)₆(H₃O)₃(NH₄)₄Cl containing pentazolate anion starting a substituted phenylpentazole, m-CPBA and iron(II) glycinate.^[1] A series of metal and nonmetal pentazolates were subsequently synthesized according to their work.

List of pentazolates

	Appearance	Dec. temp (°C)	Ref
LiN5	white	133	^[2]
LiN5·3H2O	colorless	139
[Na(N<sub>5</sub>)(H<sub>2</sub>O)]·2H2O	colorless	111.3	^[3]
[Mg(N<sub>5</sub>)<sub>2</sub>(H<sub>2</sub>O)<sub>6</sub>]·4H2O	colorless	103.5
Al(H2O)6(N5)3·9H2O	white	141.4	^[4]
[Mn(N<sub>5</sub>)<sub>2</sub>(H<sub>2</sub>O)<sub>4</sub>]·4H2O	colorless	104.1
[Fe(N<sub>5</sub>)<sub>2</sub>(H<sub>2</sub>O)<sub>4</sub>]·4H2O	pale green	114.7
Fe(H2O)6(N5)3·9H2O	reddish brown	108.9
[Co(N<sub>5</sub>)<sub>2</sub>(H<sub>2</sub>O)<sub>4</sub>]·4H2O	bright orange	58.9
AgN5			^[5]
[Pb(OH)]4(N5)4	colorless	80	^[6]
[N(CH<sub>3</sub>)<sub>4</sub>]N5	white	80.8	^[7]
(NH3OH)N5	white	104.3
[C(NH<sub>2</sub>)<sub>3</sub>]N5	white	88.1
NH4N5	white	102.0
N2H5N5	white	85.3
(CN7H6)N5		96.3	^[8]

See also

• Azide (N₃⁻)
• Diazenide (N₂²⁻)
• Nitride (N³⁻)

Notes and References

1. Zhang, C., Sun, C., Hu, B., Yu, C., & Lu, M. (2017). Synthesis and characterization of the pentazolate anion cyclo-N₅⁻ in (N₅)₆(H₃O)₃(NH₄)₄Cl. Science, 355(6323), 374–376.
2. Xu, Y., Ding, L., Yang, F., Li, D., Wang, P., Lin, Q., & Lu, M. (2022). LiN₅: A novel pentazolate salt with high nitrogen content. Chemical Engineering Journal, 429, 132399.
3. Xu, Y., Wang, Q., Shen, C. et al. A series of energetic metal pentazolate hydrates. Nature 549, 78–81 (2017).
4. Chen, L., Yang, C., Hu, H., Shi, L., Zhang, C., Sun, C., ... & Hu, B. (2022). Iron(III) and aluminum(III) complexes of cyclopentazolate anions. CrystEngComm.
5. Sun, C., Zhang, C., Jiang, C., Yang, C., Du, Y., Zhao, Y., Hu. B., Zheng. Z., Christe, K. O. (2018). Synthesis of AgN5 and its extended 3D energetic framework. Nature Communications, 9(1).
6. Yuan, Y., Xu, Y., Xie, Q., Li, D., Lin, Q., Wang, P., & Lu, M. (2022). Pentazolate coordination polymers self-assembled by in situ generated [Pb₄(OH)₄]⁴⁺ cubic cations trapping cyclo-N₅^–. Dalton Transactions, 51(15), 5801-5809.
7. Yang, C., Zhang, C., Zheng, Z., Jiang, C., Luo, J., Du, Y., Hu. B., Sun. C., Christe, K. O. (2018). Synthesis and Characterization of cyclo-Pentazolate Salts of NH₄⁺, NH₃OH⁺, N₂H₅+, C(NH₂)₃⁺, and N(CH₃)₄⁺. Journal of the American Chemical Society.
8. Yu, R. J., Liu, Y. J., Huang, W., & Tang, Y. X. (2022). A hybrid of tetrazolium and pentazolate: An energetic salt with ultrahigh nitrogen content and energy. Energetic Materials Frontiers.