Question

Buckminsterfullerene is prepared by (a) Vapourisation carbon by resistive heating (b) Passing an arc discharge between carbon electrodes in a tube containing helium at 100 torr (c) The pulsed laser vapourisation of graphite (d) None of these

Short answer

(b) Passing an arc discharge between carbon electrodes in helium at 100 torr.

Step-by-step solution

Understand the Buckminsterfullerene

Buckminsterfullerene, also known as C60, is a molecule composed of 60 carbon atoms arranged in a spherical structure. It belongs to the class of molecules known as fullerenes, which are known for their unique chemical and physical properties.

Explore How Buckminsterfullerene is Synthesized

Buckminsterfullerene is typically synthesized using methods that involve vaporizing carbon sources and rapidly condensing the vapor in an inert environment.

Analyze the Options Provided

Let's look at each option to determine which method is used in the preparation of Buckminsterfullerene: (a) Vapourisation of carbon by resistive heating: This method doesn't typically result in the desired encapsulation of carbon atoms for fullerenes. (b) Arc discharge between carbon electrodes in helium: This method is among the most common and effective for synthesizing fullerenes. It involves passing an electric arc between graphite electrodes in an inert gas atmosphere, like helium at reduced pressure (100 torr). (c) Pulsed laser vaporization of graphite: This method is effective but is less common than the arc discharge method. (d) None of these: If none of the options were correct, we would choose this.

Make a Decision

Based on the understanding that option (b), passing an arc discharge between carbon electrodes in a tube containing helium at 100 torr, is a standard method for producing Buckminsterfullerene, we select (b) as the correct answer.

Key concepts

Carbon Vaporization

Carbon vaporization is a crucial step in the synthesis of fullerenes like Buckminsterfullerene (C60). This process refers to the conversion of solid carbon into a gaseous state, which then facilitates the formation of complex carbon structures. One common method to achieve this is through high-temperature techniques, which are necessary to break the strong covalent bonds in carbon.
The vaporized carbon can then condense into different formations, such as clusters and aggregates, which eventually lead to the formation of fullerenes. The choice of vaporization method impacts the yield and quality of the fullerene structures that are produced.

Arc Discharge Method

The arc discharge method is one of the most popular and effective techniques used for synthesizing fullerenes, such as Buckminsterfullerene (C60). In this method, carbon electrodes are placed in proximity within a chamber. By applying a high-voltage electric current, an electric arc is generated between the electrodes. This arc provides the necessary energy to vaporize the carbon from the electrodes.
What makes the arc discharge method particularly advantageous is its ability to produce a significant quantity of fullerenes efficiently. The process occurs in an atmosphere of inert gas, such as helium, which helps stabilize the vaporized carbon and enhances the formation of spherical carbon structures.
Additionally, the reduced pressure environment aids in controlling the reaction to ensure optimal synthesis conditions. This method underscores the importance of electric energy in initiating carbon vaporization and fullerene creation.

Fullerenes

Fullerenes, a fascinating class of carbon-based molecules, are lauded for their unique geometrical structures and properties. These molecules are composed of carbon atoms interconnected by single and double bonds to form closed or partially closed mesh structures.
The most renowned fullerene is Buckminsterfullerene (C60), characterized by its spherical shape resembling a soccer ball, but fullerenes can also appear in other forms, such as ellipsoids and cylinders.
Their exceptional properties include high stability, unique electron affinity, and the ability to conduct electricity. These attributes make fullerenes valuable in various applications, ranging from electronics to medicine. They represent a major advancement in nanotechnology and material science.

C60 Molecule

The C60 molecule, also known as Buckminsterfullerene, stands out due to its distinctive spherical configuration of 60 carbon atoms. This arrangement mimics a geodesic dome, a concept popularized by architect Buckminster Fuller, hence the name.
Each C60 molecule consists of a network of 12 pentagons and 20 hexagons, resembling a soccer ball. This structure is not only aesthetically intriguing but also provides remarkable stability and symmetrical balance to the molecule.
The C60 molecule's versatility and robustness make it a subject of extensive research and application across diverse fields, including materials science and pharmaceuticals. It acts as a fundamental prototype for studying molecular geometry and bonding in advanced chemistry.

Helium Atmosphere

A helium atmosphere plays a pivotal role in the synthesis of Buckminsterfullerene through the arc discharge method. Helium, being an inert gas, provides a stable and non-reactive environment that prevents unwanted side reactions.
This inert gaseous environment ensures that the vaporized carbon can condense appropriately into the desired fullerene structures without interference from external reactive agents. Operating at reduced pressures, like 100 torr, improves the efficiency of the process and the quality of the fullerenes produced.
The choice of helium over other inert gases often hinges on its cost-effectiveness and its optimal performance in maintaining the delicate balance required for efficient fullerene production. This highlights the nuanced effect of atmospheric conditions on chemical processes.