Crystal Structure and Dimorphism of Silicon Tetraisocyanate Si(NCO)4
Crystal Structure and Dimorphism of Silicon Tetraisocyanate Si(NCO)4
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四异氰酸硅Si(NCO)4的晶体结构和二态性
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
M. Jansen
中科院分区：
文献类型：
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作者：
C. Schmidt;M. Jansen
四异氰酸硅酯（Si（NCO）4）是由SiCl 4和AgNCO在沸腾的甲苯中反应而得。通过拉曼和NMR光谱分析无色液体。对固体Si（NCO）4（熔点：+26 °C）的结构研究表明，它以两种多晶型形式存在。单晶X射线衍射结果表明，在-173 °C时，α-Si（NCO）4具有三斜对称性（P; a = 10.05（5），B = 10.50（2），c = 14.32（1）A，α = 91.62（1）°，β = 92.32（1）°，γ = 99.68（1）°; V = 1488.56（3）A ~ 3; Z = 8）。在T = -33 °C以上，单斜相演变，β-Si（NCO）4（P21/c; a = 10.78（3），B = 7.11（1），c = 10.27（5）A，β = 99，06（9）°; V = 777.39（1）A3; Z = 4）。研究了两种多晶型物的电荷分布。在固态下，Si（NCO）4是四面体分子，其中Si-N=C=O键在氮原子处弯曲。
Silicon tetraisocyanate Si(NCO)4 was obtained by reacting SiCl4 and AgNCO in boiling toluene. The colourless liquid was analyzed by Raman and NMR spectroscopy. Structural studies on solid Si(NCO)4 (melting point: +26 °C) have revealed it to exist in two polymorphic modifications. According to the results of single-crystal X-ray diffraction, at T = –173 °C, α-Si(NCO)4 exhibits triclinic symmetry (P; a = 10.05(5), b = 10.50(2), c = 14.32(1) A, α = 91.62(1)°, β = 92, 32(1)°, γ = 99.68(1)°; V = 1488.56(3) A3; Z = 8). Above T = –33 °C, a monoclinic phase evolves, β-Si(NCO)4 (P21/c; a = 10.78(3), b = 7.11(1), c = 10.27(5) A, β = 99, 06(9)°; V = 777.39(1) A3; Z = 4). The charge distribution was studied for both polymorphs. In the solid state, Si(NCO)4 is a tetrahedral molecule with the Si–N=C=O linkages bent at the nitrogen atoms.