[Chemistry Class Notes] on Carbide Pdf for Exam

Introduction to the Topic – Carbide

Carbide is the most common term used in inorganic chemistry and organic chemistry. Let’s come to the main question: what is carbide? The carbide is a chemical compound composed of carbon and metal or semi-metallic elements. It exists in an ionic form. The carbide group is attached to the metal or semi-metallic element with the ionic or covalent bond. The Carbide symbol is represented as [C_{2}^{-2}].  It represents that carbide ions are made up of two carbon atoms.

Carbide Formula

The carbide formula is [C_{2}^{-2}]. The Carbide formula represents that the carbide exists in a dianionic form state. On looking at the carbide ion formula you can not get an idea about the lone pairs and the hybridisation. For that, you need to have knowledge of the carbon electronic structure and its structure. 

Carbide Structure

In carbide structure, two carbon atoms are attached to each other with the three covalent bonds. From these three covalent bonds, two bonds are pi-bonds. These pi-bonds are formed by the lateral overlapping of the p-orbitals. Another bond is the sigma bond, which is formed by the head-on overlapping of the s-orbitals. The hybridization exhibited by the carbon in the carbide structure is sp. Each carbon carries one lone pair on it.

General Properties of Carbides

• Carbides generally have a very high melting point.

• Carbides are good conductors of electricity.

• Carbides are good conductors of heat.

• Carbides compounds generally possess lustre.

Preparation Methods of Carbides

It can be produced by heating metal oxide with carbon.

[CaO + 3C rightarrow CaC_{2} + CO]

It can be produced from acetylene.

[C_{2} + 2 Li rightarrow LiC_{2} + H_{2}]

Types of Carbide

The carbides can be divided into various types, depending on the nature of the bond formed between the carbide ion and the metal or semi-metallic element. 

1. Ionic Carbide – Ionic carbides are formed by the combination of highly electropositive elements like alkali metals or alkaline earth metals and carbide ions. These ions are attracted to each other by the strong electrostatic force. This type of ionic carbide exhibits a high electronegativity difference. Examples of ionic carbides are calcium carbide.

2. Covalent Carbides – Covalent carbides are formed by the combination of low electropositive elements like silicon and boron. They exhibit low electronegativity differences. Some examples of covalent carbides are: Boron carbide and silicon carbide or commonly known as carborundum (SiC).

3. Interstitial Carbides – Interstitial carbides are composed of large transition metals and carbide molecules. The carbide ions occupy the interstitial sites of the closed packed metal lattice. 

4. Intermediate Transition Metal Carbide – Intermediate transition metal carbide is composed of transition metal and the carbide ion. The size of the transition metal and the carbide ion is similar in this type of carbide. Few examples of intermediate carbides are carbides of Iron like cementite Fe₃C.

Did You Know?

• Carbides like carborundum (SiC), tungsten carbide are very hard in nature. These Carbides fall just under the diamond in terms of hardness.

• Some Carbides are used in cutting hard materials.

• Boron carbide is the hardest synthetic substance.

• Silicon carbide occurs in nature.

• Carbides are used in the metallurgy process.

• Carbiding or carburizing is the process of producing carbide coating on a metal piece. This process is used in the metallurgy process.

5 Ways Carbide is Used in the Manufacturing Industry

As you know there are a lot of metal compounds used for a definite reason and in disparate applications worldwide. A compound like a carbide stands on its own for not being only a durable metal but as well as recyclable.

Carbide contains a combination of elements such as carbon and tungsten. When the two of these elements are refurbished together they create an alloy that is resistant to rust, heat, scratches and pitting. It holds a very high density which makes carbide able to get compared with a diamond in terms of hardness.

Surgical Tools – to operate properly and inefficiently, the medical industry needs more equipment and tools. These types of equipment are specified for certain procedures and situations. Surgical tools are used recurrently and should be able to live through procedures. Carbide metals are used in surgical tools and in many other tools related to medicine that save our lives. Surgical tools which are used nowadays are mostly composed of titanium or stainless steel. This makes a great example of grafted carbide and the way it merges makes useful tools. It is grafted to titanium or stainless steel to make vital tools used for surgeries.

Mill Products – for mill products and mill inserts carbide is an efficient metal compound to be used. Over 10% of carbide is mostly used in mill products which are quite voguish. It’s manufactured in many different shapes and sizes. The type of metal carbide which comes in contact with it depends as well. This metal compound is quite variable because of the capabilities that it holds to be merged and its high density can be used to create precise applications for grading and milling.

Industrial Alloys – alloys that are specialized use carbide metal compounds the most and 17 % of them is mended with other metals. Carbide is variable and can be sharpened, combined and moulded with other metals to make useful compounds that can be utilized in electronics or other applications for commercial use. The popularly used combination of carbide is with copper, nickel, iron and silver to create different and new materials for distinguished purposes such as:

• Aeronautical industries

• Industrial gear making

• Radiation shielding.

Jewellery – as we can mould and reshape carbide to our likings it is also used in creating pieces of jewellery. We can combine it with other metals which makes carbide and jewelle
ry a perfect match. This is the modern use of carbide metals in industries. The hardness which it holds makes it more attractive for jewellery makers. It is utilized in many ways, some are in crafting rings, hoops, necklaces, etc. If carbide is cut and polished in an efficient way we can create beautiful jewellery pieces

Cemented Carbide – this is used for the creation of milling and drilling tools. Tools that are used for construction applications are made up of carbide metal compounds. This is where the market of this compound metal paves its way towards the construction applications and the formation of associated tools like drill bits, mining tips, etc. It is preferred more, over the use of stainless steel due to its resistance and hardness components.