Structure and bonding of carbon
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Intros
Topic Notes
Introduction: Understanding Carbon's Unique Structure
Welcome to our exploration of carbon's fascinating structure and its crucial role in forming large molecules! Carbon's unique atomic structure allows it to form up to four stable covalent bonds, making it incredibly versatile. This ability is key to the formation of complex organic compounds, including the building blocks of life. Our introduction video delves into the molecular structure of carbon, showcasing how its electron configuration enables it to create diverse and stable molecules. Understanding the structure of carbon is fundamental to grasping concepts in organic chemistry, biochemistry, and materials science. As we journey through this topic, you'll discover how carbon's structure contributes to the formation of everything from simple hydrocarbons to complex organic compounds. This knowledge forms the foundation for understanding life processes and the development of new materials. Let's dive in and unravel the mysteries of carbon's structure together!
The Versatility of Carbon Bonding
Carbon is a remarkable element that stands out for its unique ability to form up to four covalent bonds, making it the backbone of organic chemistry applications and life itself. The structure of a carbon atom structure enables it to form large molecules, leading to an incredible diversity of compounds. This versatility is due to carbon's electronic configuration and its position in the periodic table.
At the heart of carbon's bonding capabilities is its atomic structure. A carbon atom structure has six electrons, with two in its inner shell and four in its outer valence shell. These four valence electrons are available for bonding, allowing carbon to form up to four covalent bonds with other atoms. This tetravalent nature is what sets carbon apart from most other elements and is the key to how the structure of a carbon atom enables it to form large molecules.
Carbon can form different types of bonds, each with unique properties:
- Single bonds: These are formed when carbon shares one electron pair with another atom. Single bonds allow for rotation, giving molecules flexibility.
- Double bonds: Here, carbon shares two pairs of electrons with another atom. Double bonds are stronger and shorter than single bonds, and they restrict rotation.
- Triple bonds: In this case, carbon shares three pairs of electrons. Triple bonds are even stronger and shorter, creating rigid, linear structures.
The ability to form these various types of bonds to carbon is what makes it so versatile. Carbon can bond with itself and many other elements, creating an vast array of compounds with different properties and functions. This versatility leads to the formation of diverse carbon structures, including:
- Chains: Linear or branched sequences of carbon atoms
- Rings: Circular arrangements of carbon atoms
- 3D structures: Complex, three-dimensional molecules like fullerenes
Examples of how the structure of a carbon atom enables it to form large molecules are abundant in nature and synthetic chemistry:
- Hydrocarbons: Molecules composed of only carbon and hydrogen, ranging from simple methane to complex polymers
- Proteins: Large biomolecules with carbon backbones, essential for life
- Carbohydrates: Energy-storing molecules built around carbon chains
- DNA: The genetic material that relies on carbon-based nucleotides
The bonds to carbon in these molecules can vary in strength and orientation, allowing for an incredible range of shapes and properties. This is why carbon-based compounds can be gases (like methane), liquids (like ethanol), or solids (like diamond) at room temperature.
Understanding how carbon forms bonds is crucial in many fields, from organic chemistry applications to materials science. The unique bonding properties of carbon have led to the development of new materials like carbon nanotubes and graphene, which have revolutionary applications in technology and engineering.
In conclusion, the structure of a carbon atom, with its four valence electrons, enables it to form up to four strong covalent bonds. This tetravalent nature, combined with carbon's ability to form single, double, and triple bonds, allows for the creation of an enormous variety of molecules and materials. From the simplest hydrocarbons to the most complex biological structures, carbon's versatility in bonding is at the core of organic chemistry and life as we know it.
Allotropes of Carbon: Diamond
Diamond, one of the most fascinating allotropes of carbon, exhibits a unique and remarkable structure that gives rise to its extraordinary properties. As a carbon allotrope, diamond showcases the versatility of carbon atoms in forming different structural arrangements. The diamond structure is characterized by a highly organized and symmetrical arrangement of carbon atoms, which contributes to its exceptional hardness and other notable characteristics.
At the heart of diamond's structure lies the tetrahedral arrangement of carbon atoms. In this configuration, each carbon atom is covalently bonded to four other carbon atoms, forming a three-dimensional network. This tetrahedral geometry is crucial to understanding the question: "In the carbon allotrope diamond, how many bonds connect each carbon to other carbons?" The answer is four each carbon atom in diamond is connected to four other carbon atoms via strong covalent bonds.
These covalent bonds are exceptionally strong, resulting from the sharing of electrons between adjacent carbon atoms. The strength of these bonds is a key factor in diamond's remarkable properties. The tetrahedral arrangement, combined with these strong covalent bonds, creates a rigid and stable structure that extends throughout the entire crystal.
The diamond structure can be visualized as a repeating pattern of tetrahedra, where each carbon atom sits at the center of a tetrahedron with four other carbon atoms at its corners. This arrangement continues in all three dimensions, forming a cubic crystal system. The regularity and symmetry of this structure contribute significantly to diamond's unique properties.
One of the most well-known properties of diamond is its extreme hardness. In fact, diamond is the hardest naturally occurring substance known to science. This exceptional hardness is a direct result of its structure. The strong covalent bonds between carbon atoms and the rigid tetrahedral arrangement make it extremely difficult to deform or break the crystal structure. This property makes diamond invaluable in various industrial applications, such as cutting tools and abrasives.
Another notable property of diamond is its extremely high melting point. Diamond remains solid at temperatures far higher than most other materials, melting at approximately 3,550°C (6,422°F) under standard pressure. This high melting point is again attributed to the strong covalent bonds that hold the carbon atoms together. A significant amount of energy is required to break these bonds and disrupt the crystal structure, resulting in diamond's resistance to melting.
Interestingly, despite being composed entirely of carbon atoms (which can conduct electricity in other forms, like graphite), diamond is an excellent electrical insulator. This property arises from the nature of the bonds in its structure. In diamond, all of the carbon atoms' outer electrons are engaged in forming covalent bonds, leaving no free electrons to carry an electric current. This makes diamond a poor conductor of electricity, in stark contrast to other carbon allotropes like graphite.
The unique carbon structures in diamond also contribute to its optical properties. The regular arrangement of atoms allows light to pass through with minimal scattering, giving diamonds their characteristic transparency and brilliance when cut and polished. This property, combined with diamond's high refractive index, is what makes it so prized in jewelry.
Understanding the structure of diamond is crucial in the field of materials science and has led to the development of synthetic diamonds. By replicating the conditions under which natural diamonds form, scientists can create diamonds in laboratories, opening up new possibilities for industrial and technological applications.
In conclusion, the structure of diamond as an allotrope of carbon is a testament to the remarkable versatility of carbon atoms. The tetrahedral arrangement of carbon atoms, each connected to four others through strong covalent bonds, creates a structure of unparalleled strength and stability. This unique arrangement is the key to diamond's extraordinary properties its unmatched hardness, high melting point, and electrical insulation. By understanding and appreciating the intricacies of diamond's structure, we gain insight into one of nature's most impressive creations and open doors to innovative applications in various fields of science and technology.
Allotropes of Carbon: Graphite
Graphite, another fascinating allotrope of carbon, showcases a unique layered structure that gives rise to its distinctive properties. Understanding the graphite bond type and carbon structures is crucial to appreciating this versatile material.
Layered Structure of Graphite
Graphite consists of multiple layers of carbon atoms arranged in a hexagonal pattern. Within each layer, carbon atoms form strong covalent bonds, creating a robust two-dimensional structure. These individual layers, known as graphene sheets, are the building blocks of graphite.
Interlayer Forces
While the bonds within each layer are strong, the forces between layers are much weaker. These interlayer interactions are governed by van der Waals forces, which are relatively weak compared to covalent bonds. This unique combination of strong intralayer bonds and weak interlayer forces contributes to graphite's distinctive properties.
Properties of Graphite
The structure of graphite directly influences its properties:
- Electrical Conductivity: Graphite is an excellent conductor of electricity along its layers. The delocalized electrons in the carbon atoms can move freely within each graphene sheet, allowing for electrical conductivity of graphite.
- Softness: The weak van der Waals forces between layers make graphite soft and easily cleavable. Layers can slide over one another with minimal effort, contributing to graphite's lubricating properties.
- Lubricating Properties: The ability of graphite layers to slide past each other makes it an excellent dry lubricant, used in various applications from pencil lead to industrial machinery.
Graphite Bond Type and Carbon Structures
The carbon atoms in graphite are sp2 hybridized, forming three sigma bonds with neighboring carbon atoms in the same layer. This leaves one unhybridized p orbital perpendicular to the plane, which overlaps with adjacent p orbitals to form a delocalized pi bond system across the entire layer.
Visualizing Graphite Structure
To better understand the graphite structure, consider the following diagram:
This image illustrates the hexagonal arrangement of carbon atoms within a layer and the stacking of multiple layers to form graphite.
Applications of Graphite
The unique properties of graphite make it valuable in various applications:
- Writing instruments (pencil lead)
- Lubricants for high-temperature applications
- Electrodes in batteries and fuel cells
- Heat-resistant materials in foundry facings
- Moderator in nuclear reactors
Comparison with Other Carbon Allotropes
While graphite and diamond are both allotropes of carbon, their structures and properties differ significantly:
- Diamond: Forms a rigid 3D structure with sp3 hybridized carbon atoms, resulting in extreme hardness and electrical insulation.
- Graphite: Features a layered structure with sp2 hybridized carbon atoms, leading to softness and electrical conductivity of graphite.
Conclusion
Graphite's unique structure, combining strong covalent bonds within layers and weak van der Waals forces between layers, gives rise to its remarkable properties. Understanding the graphite bond type and carbon structures is essential for appreciating its versatility and wide range of applications in modern technology and industry. From writing instruments to advanced electronics, graphite continues to play a crucial role in our daily lives and technological advancements.
Allotropes of Carbon: Buckminsterfullerene and Carbon Nanotubes
Carbon, a versatile element, continues to surprise scientists with its remarkable allotropes. Among the more recently discovered carbon structures are buckminsterfullerene (C60) and carbon nanotubes, which have revolutionized our understanding of carbon's molecular structure and potential applications.
Buckminsterfullerene, also known as C60 or "buckyball," was discovered in 1985. This molecule consists of 60 carbon atoms arranged in a spherical structure resembling a soccer ball. The molecular structure of carbon in C60 forms a hollow cage with 20 hexagonal and 12 pentagonal faces. This unique arrangement gives buckminsterfullerene exceptional stability and strength.
The discovery of C60 opened up a new field of carbon chemistry and paved the way for the exploration of other fullerenes. These molecules showcase carbon's ability to form stable, curved structures through sp2 hybridization, a property not previously observed in other carbon allotropes like graphite or diamond.
Carbon nanotubes, another groundbreaking carbon structure, were first observed in 1991. These cylindrical molecules consist of carbon atoms bonded in a hexagonal lattice, essentially forming a rolled-up sheet of graphene. Nanotubes can be single-walled or multi-walled, with diameters ranging from a few nanometers to several tens of nanometers and lengths up to several centimeters.
The unique properties of carbon nanotubes stem from their molecular structure. The sp2 hybridization of carbon atoms in nanotubes results in incredibly strong covalent bonds, making them one of the strongest and stiffest materials known. Additionally, depending on how the graphene sheet is rolled (chirality), carbon nanotubes can exhibit either metallic or semiconducting properties.
Both buckminsterfullerene and carbon nanotubes demonstrate carbon's exceptional bonding capabilities. The ability of carbon atoms to form strong, directional covalent bonds in various configurations allows for the creation of these complex, three-dimensional structures. This versatility in bonding is due to carbon's electron configuration, which enables it to form up to four covalent bonds and participate in different hybridization states.
The unique properties of these carbon structures have led to numerous potential applications across various fields. Buckminsterfullerene has shown promise in medicine, particularly in drug delivery systems and as antioxidants. Its hollow structure allows for the encapsulation of molecules, making it an ideal candidate for targeted drug delivery. In materials science, C60 has been explored for use in organic solar cells and as a lubricant additive.
Carbon nanotubes, with their exceptional strength-to-weight ratio and electrical properties, have even more diverse applications. In electronics, they are being researched for use in transistors, sensors, and energy storage devices. The aerospace industry is exploring their potential as lightweight, high-strength materials for aircraft and spacecraft components. In medicine, carbon nanotubes are being investigated for use in biosensors, drug delivery systems, and tissue engineering scaffolds.
The environmental sector is also benefiting from these carbon structures. Both buckminsterfullerene and carbon nanotubes have shown potential in water purification technologies, capable of removing contaminants more efficiently than traditional methods. Additionally, their use in energy storage devices, such as supercapacitors and batteries, could play a crucial role in the development of renewable energy technologies.
As research continues, scientists are uncovering even more potential applications for these remarkable carbon allotropes. From enhancing the efficiency of electronic devices to revolutionizing medical treatments, buckminsterfullerene and carbon nanotubes are at the forefront of technological innovation. Their discovery has not only expanded our understanding of carbon's molecular structure but has also opened up new possibilities for solving some of the world's most pressing challenges in energy, environment, and healthcare.
The Link Between Bonding, Structure, and Properties
The structure of carbon and its unique bonding capabilities play a crucial role in determining the properties of carbon-based materials. Understanding the relationship between carbon bonding, resulting structures, and observable properties is essential for predicting the characteristics of new carbon-based materials. This connection is best illustrated through the examination of carbon's various allotropes.
Carbon atoms have the ability to form strong covalent bonds with other carbon atoms in different configurations. This versatility in bonding leads to the formation of diverse carbon structures, each with its own set of unique properties. The most common allotropes of carbon include diamond, graphite, and fullerenes, each showcasing distinct characteristics due to their specific atomic arrangements.
In diamond, carbon atoms are arranged in a tetrahedral structure, with each atom covalently bonded to four others. This three-dimensional network of strong bonds results in diamond's exceptional hardness, high melting point, and excellent thermal conductivity. The structure of carbon in diamond also accounts for its optical properties, such as its high refractive index and ability to disperse light, making it prized in jewelry and industrial applications.
Graphite, on the other hand, exhibits a layered structure where carbon atoms are arranged in hexagonal sheets. Within each layer, the atoms are strongly bonded, but the layers themselves are held together by weak van der Waals forces. This unique structure of carbon explains graphite's properties, such as its softness, electrical conductivity, and ability to act as a lubricant. The weak interlayer bonds allow the sheets to slide past one another easily, contributing to graphite's use in pencils and as a dry lubricant.
Fullerenes, including buckyballs and carbon nanotubes, represent another class of carbon allotropes with distinct structures. Buckyballs, such as C60, have a spherical structure resembling a soccer ball, while carbon nanotubes are cylindrical structures with walls made of graphene sheets. These unique carbon structures result in properties like high strength-to-weight ratios, excellent electrical and thermal conductivity, and potential applications in nanotechnology and materials science.
The relationship between carbon bonding and structure extends beyond these well-known allotropes. For instance, graphene, a single layer of graphite, exhibits extraordinary strength, flexibility, and electrical conductivity due to its two-dimensional hexagonal lattice structure. This structure of carbon atoms allows for the free movement of electrons, contributing to graphene's potential applications in electronics and energy storage.
Understanding the link between carbon bonding, structure, and properties is crucial for predicting the characteristics of new carbon-based materials. By manipulating the arrangement of carbon atoms and their bonding patterns, scientists can engineer materials with specific desired properties. For example, the development of carbon fiber composites leverages the strength of carbon-carbon bonds in a specific structural arrangement to create lightweight yet incredibly strong materials used in aerospace and sports equipment.
The structure of carbon also plays a vital role in organic compounds diversity and biochemistry. The ability of carbon to form single, double, and triple bonds with itself and other elements leads to the vast diversity of organic compounds diversity. This versatility in bonding is fundamental to the structure and function of biomolecules like proteins, carbohydrates, and nucleic acids, which are essential for life.
In the field of materials science, researchers are continually exploring new carbon structures and their potential applications. By understanding how different bonding configurations and structural arrangements affect material properties, scientists can design novel carbon-based materials with tailored characteristics. This knowledge has led to advancements in areas such as energy storage, water purification, and advanced electronics.
In conclusion, the relationship between carbon bonding, structure, and observable properties is a fundamental concept in materials science and chemistry. The diverse allotropes of carbon demonstrate how variations in atomic arrangement can lead to dramatically different properties. By leveraging this understanding, researchers can predict and engineer new carbon-based materials with specific characteristics, opening up possibilities for innovative applications across various fields. As our knowledge of carbon structures continues to expand, so too does our ability to create advanced materials that address contemporary challenges in technology, energy, and environmental science.
Conclusion: The Importance of Carbon's Structure in Chemistry and Materials Science
Understanding the structure of carbon is crucial in chemistry and materials science. Carbon's unique ability to form four stable covalent bonds allows it to create diverse structures, from simple molecules to complex organic compounds. This versatility is the foundation of life and countless materials we use daily. The various carbon structures, including diamond, graphite, and fullerenes, showcase how different arrangements of carbon atoms lead to distinct properties. Grasping carbon's structure is essential for advancing fields like nanotechnology, energy storage, and drug development. As we continue to explore carbon-based materials, new applications emerge in electronics, medicine, and environmental science. The study of carbon structures opens doors to innovative solutions for global challenges. We encourage you to delve deeper into the fascinating world of carbon-based materials and their potential to shape our future. By understanding carbon's structure, you'll gain invaluable insights into the building blocks of our universe and the materials that define our modern world.
Different forms of carbon
What is an allotrope?
Step 1: Introduction to Carbon and Its Bonding
Carbon is a unique element in the periodic table, known for its versatility in forming bonds. It is a non-metal atom that can make four covalent bonds. This ability to form four bonds allows carbon to create a variety of structures. These structures are determined by the way carbon atoms bond with each other, which can include single, double, or triple bonds. The different ways in which carbon atoms can bond and arrange themselves lead to the formation of different structures, known as allotropes.
Step 2: Definition of an Allotrope
An allotrope is a unique bonding arrangement and structure that atoms of the same element can form. In the case of carbon, its ability to form four covalent bonds allows it to create several different allotropes. These allotropes are different forms of the same element, where the atoms are bonded together in different ways, leading to different physical and chemical properties.
Step 3: Examples of Carbon Allotropes
There are several important allotropes of carbon, each with distinct properties due to their unique bonding arrangements. Three notable examples are:
- Diamond: In diamond, each carbon atom is bonded to four other carbon atoms in a tetrahedral structure. This strong bonding arrangement makes diamond extremely hard and gives it a high melting point.
- Graphite: In graphite, each carbon atom is bonded to three other carbon atoms in a planar hexagonal lattice. The layers of graphite can slide over each other, making it a good lubricant and giving it electrical conductivity.
- Buckminsterfullerene: Also known as a "buckyball," this allotrope consists of 60 carbon atoms arranged in a spherical structure. It is part of a broader category of carbon structures known as fullerenes, which also include carbon nanotubes.
Step 4: Importance of Carbon Allotropes
Carbon allotropes are significant because they demonstrate how the same element can exhibit vastly different properties based on its bonding and structure. For example, diamond and graphite are both made entirely of carbon, yet diamond is one of the hardest known materials, while graphite is soft and slippery. Understanding these allotropes helps scientists and engineers develop new materials and technologies, such as nanotechnology and advanced lubricants.
Step 5: Linking Bonding, Structure, and Properties
The study of carbon allotropes illustrates the fundamental principle that the bonding of atoms in a material determines its structure, which in turn determines its properties. By examining the different allotropes of carbon, we can see how variations in atomic bonding lead to different structural arrangements and, consequently, different physical and chemical properties. This knowledge is crucial for material science and various applications in technology and industry.
FAQs
Here are some frequently asked questions about the structure and bonding of carbon:
1. What is the atomic structure of carbon?
Carbon has 6 protons, 6 neutrons, and 6 electrons. Its electron configuration is 1s² 2s² 2p². The four valence electrons in the outer shell allow carbon to form up to four covalent bonds.
2. What are the three main structural forms of carbon?
The three main allotropes of carbon are diamond, graphite, and fullerenes (including buckminsterfullerene and carbon nanotubes). Each has a unique arrangement of carbon atoms, resulting in different properties.
3. How does the structure of a carbon atom enable it to form large molecules?
Carbon's ability to form four stable covalent bonds allows it to create long chains, branched structures, and rings. This versatility enables the formation of complex organic molecules and polymers.
4. What is the bonding model of graphite?
Graphite consists of layers of hexagonally arranged carbon atoms. Within each layer, carbon atoms are covalently bonded, forming a network of sp² hybridized orbitals. Between layers, weak van der Waals forces allow the sheets to slide past each other.
5. How many bonds can each carbon atom form?
A carbon atom can form up to four covalent bonds. This tetravalent nature allows carbon to create a wide variety of molecular structures, from simple methane to complex organic compounds and polymers.
Prerequisite Topics
Before delving into the fascinating world of carbon's structure and bonding, it's crucial to have a solid foundation in certain prerequisite topics. One of the most important areas to understand is naming organic compounds and groups. This fundamental knowledge is essential for grasping the complexities of carbon-based structures and their bonding patterns.
Understanding the principles of naming organic compounds provides a crucial framework for exploring the structure and bonding of carbon. Carbon is the backbone of organic chemistry, forming the basis for millions of different compounds. By mastering the nomenclature of carbon-based organic compounds, students can more easily identify and comprehend the various structural arrangements that carbon atoms can form.
The ability to name organic compounds is directly related to understanding carbon's bonding capabilities. Carbon's unique electronic configuration allows it to form up to four covalent bonds, leading to a vast array of molecular structures. When students are familiar with naming conventions, they can quickly recognize the types of bonds present in a molecule, whether they're single, double, or triple bonds.
Moreover, knowledge of organic compound naming helps in visualizing the three-dimensional structure of carbon-containing molecules. This spatial awareness is crucial when studying concepts like isomerism, where compounds have the same molecular formula but different structural arrangements. The naming rules often reflect these structural differences, making it easier to differentiate between various carbon-based molecules.
Understanding naming organic compounds and groups also aids in predicting the chemical properties and reactivity of carbon-based substances. The names of organic compounds often provide clues about the functional groups present, which in turn determine how the molecule will behave in chemical reactions. This knowledge is invaluable when studying more advanced topics in organic chemistry and biochemistry.
Furthermore, familiarity with organic nomenclature facilitates communication in the scientific community. When discussing complex carbon structures, having a standardized naming system ensures clarity and precision. This skill becomes particularly important in research settings or when studying more advanced topics related to carbon bonding, such as polymer chemistry or pharmaceutical development.
In conclusion, mastering the prerequisite topic of naming organic compounds and groups is an essential stepping stone towards understanding the structure and bonding of carbon. It provides the necessary language and conceptual framework to explore the rich and diverse world of carbon-based molecules, setting the stage for a deeper appreciation of organic chemistry and its applications in various scientific fields.
In this lesson, we will learn:
- To recall the definition of allotrope and name some carbon allotropes.
- How the bonding of a material leads to its specific 3d-structure.
- How the 3d structure of a material explains its unique properties using carbon allotropes as an example.
Notes:
- The carbon atom can make four covalent bonds to other atoms to fill its outer electron shell. Partly because of this high number, it has multiple forms or allotropes when samples of carbon are found in nature. An allotrope is the unique bonding arrangement and structure that atoms of an element make.
- There are three important examples of carbon allotropes: diamond, graphite, and Buckminster Fullerene (and carbon nanotubes).
- Diamond is an allotrope of carbon where each carbon atom is covalently bonded to four other carbon atoms.
- The four strong covalent bonds around each carbon atom makes a tetrahedral shape around each atom.
- This bonding creates a large lattice structure because every carbon atom is connected to four others. Diamond is practically one giant molecule because every single carbon atom is (eventually) connected to all the other atoms in the lattice through this bonding. For this reason, we say diamond has a giant covalent structure.
- This structure gives diamond its unique properties:
- Diamond is clear and colorless, as the carbon atoms in this structure reflect visible light. This also makes it shiny and lustrous which is why it is desirable in jewelry.
- Diamond is extremely hard, as deforming diamond would need you to deform the entire giant lattice that every 'diamond carbon' atom is part of. This makes it useful in cutting tools and drills.
- Diamond is insoluble in water, as interactions with the water molecules are not nearly strong enough to 'pull apart' the giant covalent lattice, so it does not dissolve.
- Diamond cannot conduct electricity, as no free electrons are found in the diamond lattice. All the electrons of all carbon atoms in the lattice are locked up in covalent bonds to each other, so no carrying of electric charge through the lattice can take place.
- Graphite is an allotrope of carbon where each carbon atom is covalently bonded to three others in layers of 2d sheets.
- The three strong covalent bonds on each carbon atom are equally spaced in 2d apart from each other. There is one electron on each carbon atom still unbonded or 'free'.
- This bonding gives graphite a structure of layers of 2-dimensional carbon atom sheets. These sheets stack on top of each other with weak stabilising interactions due to the spare electron of each carbon atom.
- This unique structure of graphite gives it its unique properties that are quite different from diamond:
- Graphite is a dark grey/black colour and is opaque as it absorbs visible light that interacts with it.
- Graphite is a smooth, slippery material because the stabilising forces between the sheets of carbon atoms are quite weak. This means applying some pressure to graphite makes the layers slide over each other quite easily. This is how pencils work: graphite layers slide off of the pencil and onto the paper we write on when we press the pencil down! It’s also used in lubricants, which are chemicals that deliberately reduce friction.
- Graphite is a good conductor of electricity,because each carbon atom has a spare electron. The spare electrons of all the carbon atoms are delocalised - they are capable of moving and carrying electric charge throughout the sheet that it is part of and through weak interactions that hold the layers close together. For this reason, graphite is used in electrodes for electrolysis experiments.
- Buckminster Fullerene is an allotrope of carbon where each carbon atom is bonded to other carbons to make a 3d spherical ball of 60 carbon atoms known as a 'buckyball'.
- Buckminster Fullerene is one of a larger category called Fullerenes.
- Some Fullerenes have tube-like structures which have a very large surface area to volume ratio. These fullerenes are called nanotubes and they have unique desirable properties such as conducting electricity and high strength combined with lightness. Many are also useful catalysts – the high surface area to volume ratio is a common property seen in nanomaterials.
- Diamond is an allotrope of carbon where each carbon atom is covalently bonded to four other carbon atoms.
- Carbon is just one example of an element which has multiple allotropes. We have only looked at three here, but another is coal which is a very important fuel. The difference between coal, graphite, diamond and Buckminster-Fullerene is simply how the carbon atoms are bonded and arranged together, they are all 'types of carbon'. A summary of the allotropes and their features are below:
Allotrope
Diamond
Graphite
Buckminster-Fullerene / carbon nanotubes
Structure
Giant covalent tetrahedral structure
Giant covalent 2d layered sheets
3d hollow sphere / 3d hollow cylinders
Melting point
Very high
Very high
High
Conducts electricity
No
Yes
Yes (nanotubes)
Hardness
Very high
Low
Uses
Cutting tools, jewelry
Pencils, electrodes
Catalysts, medical science.
- The different carbon allotropes are a good example of the bonding structure properties link in material chemistry:
- The nature of bonding in a substance leads to the material's structure.
The bonding will tell us how the negatively-charged electrons are interacting with the atoms which contain the positively-charged nucleus. This could lead to strong electrostatic forces (large positive charges attracting large negative charges like in ionic or metallic bonding), a giant covalent lattice, or a simple covalent molecule with only weak forces keeping molecules close together.- The structure of a substance leads to explaining the properties that we observe of the substance:
- Can the particles in the structure move freely and interact with electric charge? Charged particles will interact with other charged particles. If the structure has charged particles with free movement, they will be able to carry electric charge and therefore conduct electricity. If there are no charged particles or the particles are unable to move throughout the structure, this won't be possible.
This might affect the hardness and strength of the material too – if particles can/will move when a force is applied, the general structure will change shape! - What forces of attraction are keeping the whole structure together? Recall the particle model; in any substance the solid state has particles packed together with 'low energy' because the current energy is not enough to overcome the attractive forces keeping the particles together.
In a gas state, particles are far apart with 'high energy' as that high energy has overcome the attractive forces that were holding them together - that's why the particles are far apart and gases take up more volume than solids!
If those forces of attraction are strong then a lot of energy will be needed to overcome them. These structures will have a high melting/boiling point.
- Can the particles in the structure move freely and interact with electric charge? Charged particles will interact with other charged particles. If the structure has charged particles with free movement, they will be able to carry electric charge and therefore conduct electricity. If there are no charged particles or the particles are unable to move throughout the structure, this won't be possible.
- The structure of a substance leads to explaining the properties that we observe of the substance:
- The nature of bonding in a substance leads to the material's structure.