如何应用价电子对互斥理论确定分子(或离子)的空间构型

在无机化学和普通化学中,通常用杂化轨道理论阐述分子或离子的形成,采用VSEPR法(价层电子对互斥理论)可以预测分子或离子的空间结构,此方法既简单又快捷,具有较好的实际意义。

电子式书写的十种常见错误

一、漏写弧对电子 例如:(1)N2电子式的正确表示应为:N (…) (…) N:,却错误写成了N(…)(…)N.(2)NH3电子式的正确表示应为H×·N·×H..×·H,却错误写成了H×·N·×H..×·H.

常见含氧酸结构式的写法

在中学化学教学中,常遇到这样的问题:当要推断某含氧酸的化学键类型,或书写某含氧酸的结构式时,习惯解决方法是先写出该含氧酸的电子式,然后借助电子式再判断化学键类型或改写结构式。但学生往往在写电子式这一中间步骤时感到困难,因而误时较多。为此,本文提供一种快速解决这类问题的方法:

杂化与键角

在大一基础无机化学教材中,所涉及的杂化问题,皆是关于2s 轨道与2p 轨道的杂化而言的,即几乎是杂化态 sp、sp^2、sp^3的类型问题,那末在中心原子不同的杂化态分子中,其键角和立体结构是怎样的呢?从实验的事实汇总于下列表一中.

Droplet transition for plasma-MIG welding on aluminium alloys

The synchronous acquisition system of droplet image inspection and arc electric signals were established and the droplet transition characteristics of aluminum alloys were researched in the plasma-MIG welding process.Typical droplet transition modes include globular transfer mode,short circuiting transfer mode,metastable spray transfer mode and projected transfer mode.The result indicates that MIG droplet transfer frequency and droplet transfer modes are changed by introducing the plasma arc in the plasma-MIG welding process compared with the MIG welding on the aluminum alloys,which broadens the range of welding parameters when the stable welding process proceeds.The metastable spray transfer and projected transfer mode are proved to be the most optimal modes by comparing the stability of electronic signal,droplet transition,weld appearance and weld penetration.