HIGH-PRESSURE SYNTHESIS OF LISI - 3-DIMENSIONAL NETWORK OF 3-BONDED SI- IONS
HIGH-PRESSURE SYNTHESIS OF LISI - 3-DIMENSIONAL NETWORK OF 3-BONDED SI- IONS
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DOI：
10.1002/anie.199314421
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发表时间：
1993-10-01
影响因子：
16.6
通讯作者：
SEXTL, G
中科院分区：
文献类型：
--
作者：
EVERS, J;OEHLINGER, G;SEXTL, G
Li12Si，+5SiG12LiSi(A)混合物淬火至室温，卸压。事实证明，在起始混合物中使用过量的Li(10原子%)是有利的。由于反应对空气和水分的高度敏感性，所有的准备工作都是在手套箱中进行的。反应产物的吉涅尔衍射图(CuKII辐射)用Dicvol法[91]指标化，发现它具有四方晶胞和非常好的可靠性指标(F20=36)。[‘01反射的顺序和强度的进程表明LiSi和Np-LiGe“]是同型的(MgGa结构2)(Rietveld方法”’I)。单晶X射线‘31证实了粉末实验的结果。根据Zintl-Klemm的概念，[31硅在Li+Si-中，就像元素磷中的磷原子一样，有五个价电子，相应地有三个最近的硅邻居(241.7(6)(2x)和250.2(6)Pm)。Si-Si-Si键角分别为107.2(2)、110.7(2)和117.9(2)“。LiSi中的Si-Si键长为250.2 Pm，是迄今观察到的二元金属硅化物中最长的键长之一。较长的Si-Si距离仅在含有大量rm-丁基的有机金属化合物中被发现，例如在六(叔丁基)二硅烷中(Si-Si=269.7 pm)。在LiI_4Si6和LIL，Si中，典型的Si-Si键长在233-239 pm范围内。[7.S1硅化锂形成一个三维网络，其中每个Si-离子与另外三个Si-离子相连(图1)。硅离子的三维排列也是
Li12Si,+ 5 SiG12 LiSi(a) mixture was quenched to room temperature and the pressure relieved. It proved favorable to use an excess of Li (10 atom%) in the starting mixture. Due to the high sensitivity of the reactions towards both air and moisture, all preparative work with open crucibles was performed in a glove box. The Guinier diffractogram (CuKII radiation) of the reaction product was indexed by the Dicvol method [91 and found to have a tetragonal unit cell and very good reliability indices (F20= 36. M,,= 40).['01 The sequence of the reflections and the course of the intensities indicate that the structures of LiSi and NP-LiGe"] are isotypic (MgGa structurel2])(Rietveld method"'I). A single-crystal X-ray'31 confirmed the resuits of the powder experiment. According to the Zintl-Klemm concept,[31 silicon in Li+ Si-, like a phosphorus atom in elemental phosphorus, possesses five valence electrons and has, correspondingly, three nearest Si neighbors (241.7 (6)(2 x) and 250.2 (6) pm). The Si-Si-Si bond angles are 107.2 (2), 110.7 (2), and 117.9 (2)". The Si-Si bond length of 250.2 pm in LiSi is one of the longest yet observed in binary metal silicides. Longer Si-Si distances have only been found in organometallic compounds with bulky rm-butyl groups, such as in hexa (tert-buty1) disilane (Si-Si= 269.7 pm). r143'51 Typical Si-Si bond lengths in LiI4Si6 and Lil, Si, lie in the range 233-239 pm.[7. s1 Lithium silicide forms a three-dimensional network in which each Si-ion is connected with three further Si-ions (Fig. 1). A three-dimensional arrangement of Si-ions is also