Phosphonium Salts - Phosphonium Enes

[ I ] Phosphorus salts of type [PH ₄ ]X (X is a halogen or other anion) that correspond to ammonium salts of nitrogen. PH ₄ ⁺ is less stable than NH ₄ ⁺ and has a weaker basicity. Phosphonium iodide: [PH ₄ ]I (161.91). It is obtained by hydrolyzing a mixture of diphosphane P ₂ H ₄ and yellow phosphorus, or by reacting yellow phosphorus with iodine in carbon disulfide. Colorless tetragonal crystal. Distorted cesium chloride structure. Contains tetrahedral PH ₄ ⁺ . pH approximately 1.02 Å. Sublimation point 62.5 °C (melting point under vapor pressure is 18.5 °C). In the presence of traces of water or alcohol, it decomposes to HI and the phosphine PH _3. It decomposes explosively when heated suddenly. It is used as a raw material for the synthesis of PH ₃ and phosphonium salts in the laboratory. [CAS 12125-09-6:[PH ₄ ]I] [ II ] [PH ₄ ]X in which all or some of the H's are replaced with hydrocarbon groups R is called an alkyl (or aryl) phosphonium salt (or simply phosphonium salt for short). Of these, [PR ₄ ] ⁺ X- ^, in which all H's are replaced with R, is called a quaternary phosphonium salt. It is obtained by the reaction of [PH ₄ ]I with RI. Most are hygroscopic solids and relatively stable. It reacts with phenyllithium to produce phosphorane.

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

【Ⅰ】窒素のアンモニウム塩に相当するリンの[PH₄]X型の塩(Xはハロゲン，またはそのほかの陰イオン)をいう．PH₄^＋はNH₄^＋に比べて不安定で，塩基性も弱い．ヨウ化ホスホニウム(phosphonium iodide)：[PH₄]I(161.91)．ジホスファンP₂H₄と黄リンの混合物を加水分解するか，二硫化炭素中で黄リンとヨウ素を反応させると得られる．無色の正方晶系結晶．ひずんだ塩化セシウム型構造．正四面体型のPH₄^＋を含む．P-H約1.02 Å．昇華点62.5 ℃(蒸気圧下の融点は18.5 ℃)．微量の水またはアルコールの存在で分解してHIとホスフィンPH₃になる．急に加熱すると爆発的に分解する．実験室でのPH₃，ホスホニウム塩の合成原料に用いられる．[CAS 12125-09-6:[PH₄]I]【Ⅱ】[PH₄]XのHの全部または一部を炭化水素基Rで置換したものをアルキル(またはアリール)ホスホニウム塩(または略称して単にホスホニウム塩)という．このうち，H全部をRに置換した[PR₄]^＋ X^－を第四級ホスホニウム塩という．[PH₄]IとRIとの反応で得られる．多くは吸湿性の固体で，比較的安定である．フェニルリチウムと反応してホスホランを生じる．

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