What is the difference between lattice and unit cell? What is lattice energy is related to what

Put each structural unit in the crystal (atoms, molecules, clusters of atoms.

or ion) abstracted into a point, the equally spaced points are arranged into a row of straight lattices, and the straight lattice is arranged in parallel to form a plane lattice, and many plane lattices are arranged in parallel to form a three-dimensional space.

Lattice. A parallelepiped formed in a lattice with three periods a, b, and c as the side lengths in a three-dimensional space.

The lattice is called a lattice. (So, a lattice is a geometric concept, a simplified description abstracted from the crystal structure).

If the structural units that make up the crystal are placed at the nodes of the crystal lattice, the actual structure corresponding to the crystal lattice can be obtained, the unit cell.

This is the basic definition of both. It can be seen that the unit cell is a parallelepiped with the same size and shape as the lattice, including not only the form and size of the lattice, but also the content of the structural unit corresponding to the lattice node.

In order to describe the structure of the crystal, we take the atoms that make up the crystal as a point, and then connect these points representing the atoms with imaginary line segments, and draw a lattice-like spatial structure like the one shown in the figure. This geometric lattice used to describe the arrangement of atoms in a crystal is called a lattice. Since the arrangement of atoms in the crystal is regular, the smallest unit that can fully express the lattice structure can be taken out of the crystal lattice, and this smallest unit is called.

Crystal cell. Many unit cells with the same orientation make up the grains.

Crystal lattice. It is the atoms that are regularly connected by lines to form a shape like a Rubik's cube.

Crystal cell. It can be understood as a "cell" and is a part of the crystal. The arrangement of atoms in molecules, atoms or ions is composed of a certain order, and due to the repeatability of the crystal order, the unit cell is the smallest unit structure in the crystal and there is no repetition!

Lattice energy refers to the energy absorbed by the ion crystal when it becomes a gaseous positive ion and a gaseous negative ion under standard conditions, and it is a parameter to measure the stability of the crystal lattice. It is related to the ionic radius, ionic charge, and electron shell configuration of the ion.

Examples of relevant factors:

1. Ionic radius.

For example, as the radius of the halide ion increases, the lattice energy of the halide decreases.

2. Ionic charge.

**The lattice energy of a compound is much greater than that of a low-valent ionic compound.

3. Electron layer configuration.

Cu and Na have similar radii, the same ionic charge, but Cu is an 18-electron configuration and polarizes the anion, therefore.

cu₂s<ᵁna₂s。

It is mainly related to the bond energy between crystal atoms, the form of atomic arrangement and the lattice constant.

Lattice energy is the energy of gaseous ions when they form crystals, so it is related to the charge of the ions, the more charges, the greater the attraction, and the arrangement between the ions.

Lattice energy can also be said to be the energy required to destroy 1mol of crystal, turning it into completely separated free ions. The greater the lattice energy, the stronger the ionic bond and the more stable the crystal.

There are two values of lattice energy. The first is the theoretical calculated value. It is calculated by the following approximate formula based on the ion crystal model, considering the attraction between any ion and the surrounding heterogeneous ions, as well as the repulsion between the other ions of the same name.

The magnitude of the stability lattice energy determines the stability of ionic crystals, and it can be used to explain and predict many physical and chemical properties of ionic crystals. For example, according to the magnitude of the lattice energy, the electron affinity potential that is difficult to be measured from experiments can be obtained, the heat of dissolution of ionic compounds can be obtained, and the thermal effect of dissolution can be obtained.

The main influencing factor is the ionic charge, the higher the charge, the greater the lattice energy.

The second is the ionic radius, the smaller the ion, the greater the lattice energy.

Then down is the ion configuration, the more d electrons in the outer shell of the ion, the more likely it is to polarize the ion, and the corresponding lattice energy will decrease.

According to the element vector complex, the spatial lattice system can be divided into lattices, and the lattice can be used to cut bai

The actual crystal, get a du

These parallelepiped hexahedrons are no longer abstract geometry, but include the concrete constituent substances of crystals, called unit cells. The unit cell is the basic repeating unit in the crystal structure. Emphasizing the specific situation of each smallest repeating unit, according to the selected element vector, the lattice points are connected to the line, and the spatial lattice is divided into parallelepipeds and stacked (at this time, each vertex is shared by eight parallelepipeds), and the lattice formed by the lines formed by the spatial lattice is called the lattice.

The emphasis is on the arrangement of the spatial lattice.

In actual crystals, the particles are arranged in a variety of ways, in order to facilitate the study of atoms, molecules, or ions.

The arrangement of the crystals is approximately regarded as the ideal crystals without misalignment, ignoring their materiality, and abstracting them into countless geometric points of regular arrangement and space. These points represent the center of the atom (molecule or particle), or the center of the group of atoms or molecules that are equal to each other, and the surrounding environment of each point is the sameCrystal cell. It is to take out the most basic unit from the lattice that can still maintain the characteristics of the latticeCrystal lattice. A spatial lattice that connects the array points by a series of parallel straight lines.

The differences and connections between unit cell and lattice are:

1. Difference: The lattice can be regarded as a cubic lattice composed of atomic abstraction points, which can be extended infinitely. The unit cell is a structure that can cover the entire crystal lattice through a certain regular translation, and the single cell is its most small structure, which contains only one lattice.

2. Connection: If the structural units that make up the crystal are placed on the nodes of the crystal lattice, the actual structural unit cells corresponding to the crystal lattice can be obtained.

Crystal, lattice, unit cell connection:

A crystal is a solid with internal particles arranged periodically and repeatedly in three-dimensional space, while a lattice is a structural particle (molecule, atom, ion) that makes up a crystal is regularly arranged at a certain point in space. It is a geometric concept, a simplified description abstracted from the structure of a crystal.

The unit cell is a representation of a crystal and is the smallest unit in a crystal. If the crystals are juxtaposed, the crystals are obtained. In general, the unit cells are parallelepiped, and the whole crystal can be seen as the juxtaposition of countless unit cells without gaps. <>

First, the nature is different.

1. Lattice chaotic nature: The spatial lattice with the regular arrangement of atoms in the crystal is called the lattice.

2. Grain properties: small crystals with irregular shapes that make up polycrystals, and each grain is sometimes composed of several subcrystals with slightly different orientations.

Second, the characteristics are different.

1. Crystal lattice point: because the distribution of atoms, ions or molecules that make up the crystal in the crystal is in line with the law of space lattice and behaves in the form of lattice.

2. Grain characteristics: Grains can be composed of single crystal and polycrystal. Grains with uniform orientation form single crystals, and grains with different orientations form polycrystals.

Expand the information of the paulownia shelter:

The size and shape of the grains have a significant impact on the properties of the material. Generally speaking, the finer and more uniform the grain, the better the overall properties of the material. Therefore, through the measurement of grain size, the properties of the material can be preliminarily judged.

When cold-deformed metals are reheated and annealed, their structure and properties change. The annealing process can be divided into three stages: recovery, recrystallization, and grain growth.

The lattice energy with high charge is larger, and when the charge is the same, look at the ionic radius and the smaller lattice energy is larger. Whether the lattice can be measured directly or not can only be measured by thermodynamic cycling.