tungsten diboride

• 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: tungsten diboride
• 化学式: B₂W
• 分子量: 205.472
• InChiKey: ZVHBVMXMTNMFKK-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  -2.37
• 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：

  钨 、 tungsten diboride 以 melt 为溶剂， 生成 tungsten monoboride
  参考文献：
  名称：

  Effect of Defects in the Formation of AlB₂-Type WB₂ and MoB₂

  摘要：

  Tungsten diboride, VVBv usually has a hexagonal structure with the space group P6(3)/mmc (number 194); and molybdenum diboride, MoB2, has a trigonal structure with R (3) over barm (number 166). Other than these phases, both diborides are reported to have a phase with an AlB2-type structure (P6/mmm, number 191). AlB2-type MoB2 is easy to synthesize and has been extensively studied, whereas AlB2-type WB2 is very difficult to synthesize and has appeared only once in a report by Woods et al. in 1966 (Woods, H. P.; Wawner, Jr., F. E.; Fox, B. G. Science 1966, 151, 75.) We have investigated these diborides by means of first-principles calculations and found that boron defects are responsible for the difference in their synthesizability. AlB2-type MoB2 became stable enough with some boron defects added, while AlB2-type WB2 became minimally stable, suggesting it may not actually exist. Following our calculations, we attempted to synthesize AlB2-type WB2 with the optimum quantity of boron defects but observed no trace of it. We conclude, from both calculations and experiments, that AlB2-type WB2 does not exist stably in the W-B phase diagram and that the compound produced in Woods et al.'s report might have contained some impurities.

  DOI：

  10.1021/ic400587j
• 作为产物：
  描述：

  magnesium diboride 、 六氯化钨 850.0 ℃ 、1.0 Pa 条件下， 反应 5.0h， 生成 tungsten diboride
  参考文献：
  名称：

  金属间化合物硼化钨的多晶相和析氢的相变电催化性能

  摘要：

  合成了W2B，WB，WB2和WB3四种化学计量的WB金属间相，并对其氢演化电催化性能和电子结构进行了比较研究。发现对氢气析出反应的电催化活性首先从W2B升高到WB2，然后降低；然后从W2B升高到WB2。并且可以根据W的d轨道和B的sp轨道之间不同的杂交程度来合理化这种活动趋势。

  DOI：

  10.1039/d0cc06072k

文献信息

• Superhard Tungsten Diboride-Based Solid Solutions
  作者：Lisa E. Pangilinan、Christopher L. Turner、Georgiy Akopov、Mackenzie Anderson、Reza Mohammadi、Richard B. Kaner

  DOI：10.1021/acs.inorgchem.8b02620

  日期：2018.12.17

  hardest solid solution (W0.92Ta0.08B2) showed oxidation resistance up to ∼570 °C, approximately 70 °C higher than that of tungsten carbide (WC). Although pure WB2 is known not to be superhard, these results demonstrate the formation of superhard solid solutions through the substitution of tungsten by small amounts of transition metals. This increase in hardness can be attributed to solid solution hardening

  二硼化钨（WB 2）的固溶体，钨（W）被钽（Ta）和铌（Nb）取代的程度不断增加，范围从0到50 at。以金属为基准的％-是通过电阻电弧熔化合成的。使用粉末X射线衍射（PXRD）进行相鉴定，能量色散X射线光谱学和X射线光电子能谱分析进行元素表征，元素组成，维氏显微压痕进行硬度测量以及热重分析进行热稳定性分析。发现溶解度极限小于8at。Nb的百分比小于10 at。Ta的％，由PXRD确定。维氏硬度（H v）在0.49 N下测量6 at。时的值分别为40.3±1.6和41.0±1.2 GPa。％Nb和8 at。分别为％Ta取代。另外，最坚硬的固溶体（W 0.92 Ta 0.08 B 2）显示出高达〜570°C的抗氧化性，比碳化钨（WC）的抗氧化性高约70°C。尽管已知纯WB 2不是超硬的，但这些结果证明了通过用少量过渡金属替代钨来形成超硬固溶体。硬度的增加可归因于固溶硬化。
• Gmelin Handbuch der Anorganischen Chemie, Gmelin Handbook: B: MVol., 4.4, page 31 - 35
  作者：

  DOI：——

  日期：——
• Thermal expansion studies on the group IV–VII transition metal diborides
  作者：Bertil Lönnberg

  DOI：10.1016/0022-5088(88)90219-6

  日期：1988.7
• Gmelin Handbuch der Anorganischen Chemie, Gmelin Handbook: W: MVol., 1.3.1, page 86 - 90
  作者：

  DOI：——

  日期：——
• Moisson, H., Comptes Rendus Hebdomadaires des Seances de l'Academie des Sciences, 1896, vol. 123, p. 13
  作者：Moisson, H.

  DOI：——

  日期：——