lanthanum disilicide

• 分子结构分类: 无机化合物 - 混合金属/非金属化合物 - 各种混合金属/非金属
• 英文名称: lanthanum disilicide
• 化学式: LaSi₂
• 分子量: 195.076
• InChiKey: KGNKZRQBUGRARP-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  -2.9
• 重原子数：
  3.0
• 可旋转键数：
  0.0
• 环数：
  0.0
• sp3杂化的碳原子比例：
  0.0
• 拓扑面积：
  0.0
• 氢给体数：
  0.0
• 氢受体数：
  0.0

反应信息

• 作为反应物：
  描述：

  lanthanum disilicide 、 硅烷 以 neat (no solvent) 为溶剂， 生成 lanthanum silicide
  参考文献：
  名称：

  Phase diagram of the La–Si binary system under high pressure and the structures of superconducting LaSi5 and LaSi10

  摘要：

  The La-Si binary phase diagram under a high pressure of 13.5 GPa was experimentally constructed. New superconducting silicides LaSi5 and LaSi10 were found, which have peritectic decomposition temperatures at 1000 and 750 degrees C, respectively. The single crystal X-ray structural analysis revealed that there are two polymorphs in LaSi5. The alpha-form obtained by heating a molar mixture of LaSi2 and 3 Si at about 700 degrees C or by a rapid cooling from 1000 degrees C under pressure crystallizes with the space group C2/m and the lattice parameters a = 15.11(3), b = 4.032(6), c = 8.26(1) angstrom, and beta = 109.11(1)degrees. The beta-form obtained by a slow cooling from 800-950 degrees C to 600 degrees C under pressure has the same space group but with slightly different lattice parameters, a = 14.922(7), b = 3.906(2), c = 8.807(4) A, and beta = 107.19(1)degrees. The beta-form is formed during the incomplete transformation of the alpha-form on cooling, and has always been obtained as a mixture with the alpha-form. The compound can be characterized as a Zintl phase with a polyanionic framework (3)(infinity)[Si-5](3-) with large tunnels running along the b axis hosting lanthanum ions. In the beta-form, three of the five Si sites are disordered. The two polymorphs contain one dimensional sila-polyacene ribbons, Si ladder polymer, running along the b axis. The alpha-form showed superconductivity with the transition temperature T-c of 11.5 K. LaSi10 crystallizes with the space group 6(3)/mmc and the lattice parameters a = 9.623(4), c = 4.723(3)angstrom. It is composed of La containing Si-18 polyhedra (La@Si-18) of hexagonal beer-barrel shape, which form straight columns by stacking along the c-axis via face sharing. One-dimensional columns of La@Si-18 barrels are edge-shared, and bundled with infinite Si trigonal bipyramid chains via corner sharing. The Si atoms in the straight chains have a fivefold coordination. LaSi10 became a superconductor with T-c = 6.7 K. The ab initio calculation of the electric band structures showed that alpha-LaSi5 and LaSi10 are metallic, and the conduction electrons mainly come from Si-3p orbitals. (C) 2009 Elsevier Inc. All rights reserved.

  DOI：

  10.1016/j.jssc.2009.05.010
• 作为产物：
  描述：

  三氢化镧 、 硅烷 以 melt 为溶剂， 生成 lanthanum disilicide
  参考文献：
  名称：

  673 K 时 La-Ni-Si 系统中的相关系

  摘要：

  摘要 通过 X 射线衍射 (XRD)、差热分析 (DTA)、扫描电子显微镜 (SEM) 和电子探针微量分析 (EPMA) 研究了 673 K 下 La-Ni-Si 三元体系中的相关系。所有的相关系都是在 673 K 下研究的。在这个温度下，已经确认了 14 种三元化合物的存在。该部分由35个单相区、78个二相区和47个三相区组成。在 673 K 时，Si 在 Ni、La 2 Ni 7 、LaNi 5 和 La 2 NiSi 中的最大固溶度分别约为 9、3、8.33 和 5 at.%。几种三元化合物形成一个均质区，可以表示为 LaNi 11.6–9.5 Si 1.4–3.5 、LaNi 8.8–8.4 Si 4.2–4.6 和 LaNi 7.8–6.5 Si 5.2–6.5 。

  DOI：

  10.1016/s0925-8388(03)00698-4

文献信息

• Phase relationships in the La–Ni–Si system at 673 K
  作者：Huaiying Zhou、Qingrong Yao、Songliu Yuan、Jingqi Liu、Heixia Deng

  DOI：10.1016/s0925-8388(03)00698-4

  日期：2004.3

  The phase relationships in the La–Ni–Si ternary system at 673 K were investigated by X-ray diffraction (XRD), differential thermal analysis (DTA), scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). All phase relationships were studied at 673 K. At this temperature, the existence of 14 ternary compounds has been confirmed. This section consists of 35 single-phase regions, 78

  摘要 通过 X 射线衍射 (XRD)、差热分析 (DTA)、扫描电子显微镜 (SEM) 和电子探针微量分析 (EPMA) 研究了 673 K 下 La-Ni-Si 三元体系中的相关系。所有的相关系都是在 673 K 下研究的。在这个温度下，已经确认了 14 种三元化合物的存在。该部分由35个单相区、78个二相区和47个三相区组成。在 673 K 时，Si 在 Ni、La 2 Ni 7 、LaNi 5 和 La 2 NiSi 中的最大固溶度分别约为 9、3、8.33 和 5 at.%。几种三元化合物形成一个均质区，可以表示为 LaNi 11.6–9.5 Si 1.4–3.5 、LaNi 8.8–8.4 Si 4.2–4.6 和 LaNi 7.8–6.5 Si 5.2–6.5 。
• Contact reaction between Si and rare earth metals
  作者：R. D. Thompson、B. Y. Tsaur、K. N. Tu

  DOI：10.1063/1.92442

  日期：1981.4

  Reactions between Si and thin films of rare‐earth metals (Gd, Dy, Ho, Er, plus Y and La) in the temperature range of 275–900 °C have been studied by using x‐ray diffraction and ion backscattering spectrometry. The disilicides of these metals are apparently the first phase to form, forming rapidly within a narrow temperature range (325–400 °C), and are stable up to 900 °C. The growth does not follow

  已经使用 X 射线衍射和离子背散射光谱法研究了 Si 与稀土金属（Gd、Dy、Ho、Er、加上 Y 和 La）薄膜在 275-900°C 温度范围内的反应。这些金属的二硅化物显然是第一个形成的相，在狭窄的温度范围 (325–400 °C) 内迅速形成，并在高达 900 °C 时保持稳定。增长不遵循分层增长模式。
• The heat capacity of PrSi2
  作者：S.K. Dhar

  DOI：10.1016/0304-8853(94)90308-5

  日期：1994.4

  The heat capacity of PrSi2 and nonmagnetic LaSi2 has been measured from 2 to 24 K. The data support the earlier observation of two peaks in the ac susceptibility of PrSi2, reported by S. Labroo et al. A substantial fraction of the specific heat of PrSi2 in the paramagnetic region is due to the Schottky contribution arising from the crystal field split levels. It is essential to consider this contribution for the correct interpretation of the data.
• Resonant photoemission in CeAl, Ce<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Si</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>, and La<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Si</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>
  作者：J. M. Lawrence、J. W. Allen、S. -J. Oh、I. Lindau

  DOI：10.1103/physrevb.26.2362

  日期：——
• Bolgar; Gorbachuk; Blinder, Russian Journal of Physical Chemistry, 1996, vol. 70, # 7, p. 1100 - 1104
  作者：Bolgar、Gorbachuk、Blinder、Moiseev

  DOI：——

  日期：——