Hydrogen Azide - Azikasuiso

_HN3 (43.03). Also known as hydronitrile acid and hydrazoic acid. It is obtained by reacting sodium azide with acid. It is a colorless, volatile liquid at room temperature. Density is 1.13 g cm ^-3 . Melting point is -80°C, boiling point is 35.7°C. The gas molecule has a linear NNN structure and a bent linear structure with an angle of ∠HNN of 114°. It is unstable and decomposes when heated or exposed to light. An aqueous solution of hydrogen azide is called hydrazoic acid and is a weak acid.

HN ₃ + H ₂ OH ₃ O ⁺ + N ₃ ^- ( _{p Ka} 4.77 (298 K))

Aqueous solution is fairly stable, but decomposes when exposed to light. Damages skin and mucous membranes. Causes hypotension. Toxic. [CAS 7782-79-8]

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

HN₃(43.03)．窒化水素酸，ヒドラゾ酸ともいう．アジ化ナトリウムに酸を作用させると得られる．室温では無色，揮発性の液体．密度1.13 g cm^－3．融点－80 ℃，沸点35.7 ℃．気体分子は，N-N-Nは直線状で，∠H-N-Nは114°の折れ線形構造である．不安定で，加熱，光などにより分解する．アジ化水素の水溶液はアジ化水素酸といい，弱酸性を示す．

HN₃ ＋ H₂O H₃O^＋ ＋ N₃^－(pK_a 4.77(298 K))

水溶液はかなり安定であるが，光照射で分解する．皮膚，粘膜をおかす．血圧降下を起こす．有毒．[CAS 7782-79-8]

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