Lattice Structures

If you’ve ever wondered how ionic, covalent, and metallic bonding are alike, here’s one thing: they can all make lattice structures. But what does that even mean? Basically, each lattice has its own structure and bonding, which makes them different from each other. And because of these differences, they also have different physical properties like how well they dissolve, when they melt, and how well they conduct electricity. It all comes down to their chemical structures.

So, let’s break it down. First, we’ll talk about what a lattice structure is. After that, we’ll dive into the three types: ionic, covalent, and metallic. And finally, we’ll look at the specific qualities of each one. Along the way, we’ll give some examples so you can visualize it better.

When we say “lattice,” we mean a three-dimensional pattern of ions or atoms in a crystal. And that pattern is determined by the type of bonding happening between the particles. Ionic lattices are formed by the attraction between positive and negative ions. Covalent lattices happen when atoms share electrons. And metallic lattices are made by the sharing of electrons between metal atoms.

Each type of lattice has its own unique properties. For example, ionic lattices are usually hard and brittle, while metallic lattices are malleable and ductile. Covalent lattices can have varying qualities depending on the atoms involved.

So, there you have it. Lattice structures are pretty fascinating when you think about all the different types and properties they can have.

Types Of Lattice Structures

Giant Ionic Lattice

Do you remember learning about Ionic Bonding in our previous articles? Just to refresh your memory, this happens when electrons are transferred from metals to non-metals, causing metals to lose electrons and become positively charged ions (cations), while non-metals gain electrons and become negatively charged. When this happens, strong electrostatic forces form between the oppositely charged ions, creating a lattice structure. This type of compound can form giant ionic lattices, which are made up of a large number of the same ions repeating in a pattern.

For example, let's look at sodium chloride (NaCl). It's a giant ionic lattice where Na+ ions and Cl- ions attract each other in opposite directions. The ions are packed together in a cubic shape, with the negative ions being larger than the positive ones. It's pretty cool to think about how all these ions come together to form something we use in our everyday lives!

  

how to draw a sodium chloride lattice
Diagram of a giant ionic lattice of NaCl

Another example of a giant ionic lattice is Magnesium Oxide (MgO). Just like NaCl, Mg2+ ions and O2- ions are attracted to each other in its lattice, and they are also packed together in a cubic shape. The negative ions of Oxygen are larger than the positive ions of Magnesium.

Moving on to Covalent Bonding, this type of bonding occurs between non-metals only. It's a strong electrostatic attraction between two positive nuclei and the shared pair of electrons between them. There are two types of structures that can contain covalent bonding: giant covalent structures and simple covalent structures. The difference between them is that the electrostatic attraction holding giant structures together is stronger than the one holding simple structures.

Some examples of simple molecular lattices are iodine, buckminsterfullerene (C60), and ice. Buckminsterfullerene (C60) is a unique molecule made up of only carbon atoms arranged in 20 hexagonal rings and 12 pentagonal rings, forming a spherical structure. It's pretty amazing how different types of bonding can create such fascinating structures!

 

Diagram representing buckminsterfullerene (C60)
Diagram representing buckminsterfullerene (C60)

It's fascinating to see how different substances can form unique crystal lattice structures. For example, when water freezes, the H2O molecules arrange themselves in a crystal lattice structure, and the resulting ice takes up more space than the liquid form because of the extra space between the molecules. Iodine, on the other hand, forms a face-centric-cubic lattice, which is a cube of molecules with other molecules arranged on the center of the faces of the cube. It can be a little hard to visualize, but if you look at the lattice from above, you'll notice that the molecules on the right and left side of the cube are aligned in the same way, while those in the middle are aligned differently.

Moving on to giant molecular lattices, some examples are graphite, diamond, and silicon (IV) oxide. Each of these substances has a unique lattice structure due to the arrangement of atoms or molecules within them. It's amazing to think about how the microscopic structure of a substance can determine its physical properties and behavior!

Shapes of the giant molecular lattices

It's amazing how the arrangement of atoms or molecules can determine the properties and uses of a substance. Graphite, made entirely of carbon atoms, has a unique lattice structure where carbon atoms are arranged in hexagonal rings. Millions of carbon atoms can exist in a single molecule of graphite, forming a giant covalent structure. On the other hand, diamond, another allotrope of carbon, has a tetrahedral structure where each carbon atom makes 4 single covalent bonds with 4 other carbon atoms. This arrangement makes diamond the hardest material in the world.

Silicon (IV) oxide, also known as silica, is another example of a giant covalent structure with atoms arranged in a tetrahedral geometry. Silica is the major constituent of sand and is very hard due to its structure. It's fascinating to see how the unique lattice structures of these substances give them their distinct properties and make them useful in a variety of applications.

Metallic Lattices

It's intriguing to learn about the structure of metallic lattices and how they form through metallic bonding. When atoms of metals are closely packed together, they create a regular shape known as a giant metallic lattice. Within this lattice, there are free electrons in the outer shell of the metal atoms, also known as delocalized electrons. These electrons are free to drift around the structure, allowing positive ions to form and causing metallic bonding to occur. The strong electrostatic attraction between the delocalized electrons and the positive metal ions is what gives metals their unique properties, such as high electrical and thermal conductivity.

An example of a metallic lattice is calcium, where the ions have a 2+ charge. Copper, on the other hand, forms a face-centred-cubic (FCC) lattice. In an FCC lattice, there is an atom at each vertex of the cube, and there is an atom at the center of each face of the cube. Other metals also form giant metallic structures as they consist of millions of atoms arranged in specific lattice structures.

Overall, the unique properties of metals are due to their metallic bonding, which is a result of the arrangement of atoms in metallic lattices and the presence of delocalized electrons allowing for the free flow of electric current.

Characteristics Of Lattices

Ionic Lattices

Giant ionic lattices have very high melting and boiling points because of the strong attraction holding the ions together. They conduct electricity but only when they are dissolved or molten. When ionic lattices are in a solid state, their ions are fixed in position and cannot move so electricity is not conducted. Giant ionic lattices are soluble in water and polar solvents, however, they are insoluble in non-polar solvents. Polar solvents have atoms that have a large difference in electronegativity. Non-polar solvents contain atoms with a relatively small difference in electronegativity.

Covalent Lattices

It's fascinating to learn about the properties of simple and giant covalent lattices. Simple covalent lattices have low melting and boiling points because they have weak intermolecular forces between the molecules. As a result, only a small amount of energy is required to break the lattice. Additionally, they do not conduct electricity in any of the states because there are no ions or delocalized electrons to move around the structure and carry a charge. Simple covalent lattices are more soluble in non-polar solvents and are insoluble in water.

In contrast, giant covalent lattices have high melting and boiling points because a large amount of energy is required to break the strong bonds between the molecules. Most of these compounds cannot conduct electricity because there are no free electrons available to carry a charge. However, graphite is a unique giant covalent lattice that can conduct electricity because it has delocalized electrons. These types of lattices are insoluble in water as they don't contain any ions.

Overall, the properties of covalent lattices are determined by the strength of the bonds between the molecules and the presence or absence of delocalized electrons or ions. Understanding these properties is essential in understanding the various applications and uses of these compounds in different industries.

Metallic Lattices

Giant metallic lattices have moderately high melting and boiling points due to the strong metallic bonding that exists between the delocalized electrons and positive metal ions. These lattices can conduct electricity when solid or liquid because free electrons are available in both states and can drift around the structure carrying an electric charge. However, they are insoluble in water due to the metallic bonds being very strong. Nonetheless, they can be soluble in only liquid metals.

In summary, lattice structures are three-dimensional arrangements of ions or atoms in a crystal. Giant ionic lattices are made up of large numbers of the same ions arranged in a repeated pattern, held together by strong electrostatic attraction. There are two types of covalent lattices, giant covalent lattices, and simple covalent lattices, with the electrostatic attraction holding giant structures together being stronger than the electrostatic attraction holding simple structures. Lastly, metals form giant metallic lattice structures that consist of atoms that are closely packed together in a regular shape, held together by strong metallic bonding.

Lattice Structures

What is lattice structure?

 A lattice is a three-dimensional arrangement of ions or atoms in a crystal. 

What are lattice structures used for?

Lattice structures can be used for additive manufacturing.

What are the types of lattice structures?

- Giant ionic lattices- Covalent lattices- Metallic lattices

What is an example of a lattice structure?

An example is sodium chloride, NaCl. The ions in this structure are packed in a cubic shape. 

How do you draw the sodium chloride lattice structure?

1. Draw a square2. Draw an identical square offset from the first one.3. Next, join the squares together to make a cube.4. Then, divide the cubes into 8 smaller cubes.5. Draw three lines through the centre of the cube,  from the centre of each face to the centre of the opposite face.6. Add the ions, but remember the negative ions (Cl-) will be larger in size than the positive ions.

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