Explain the characteristics and formation principle of polycrystalline, single crystal and amorphous diffraction patterns

Describes the characteristics and formation principle of polycrystalline, single crystal and amorphous diffraction patterns as follows:

1, long-range ordering: the regular arrangement of atoms inside the crystal within at least the micrometer range.

2, homogeneity: the macroscopic properties of the internal parts of the crystal are the same.

3, anisotropy: different physical properties in different directions in a crystal.

4, symmetry: the ideal shape of the crystal and the internal structure of the crystal have specific symmetry.

5, self-limiting: crystals have the property of spontaneously forming closed geometric polyhedra.

6, dissociation: the crystal has the property of cleavage along the crystal faces of certain definite orientations.

7, minimum internal energy: the minimum internal energy of a molded crystal.

8, crystal plane angle conservation: belonging to the same kind of crystal two corresponding crystal plane between the constant angle.

Crystals are defined as follows:

Crystals are solids in which atoms, ions, or molecules are arranged in space to form a geometrical shape with a certain regularity in accordance with a certain periodicity in the process of crystallization.

There are three characteristics of crystals: crystals have a neat and regular geometric shape, crystals have a fixed melting point, in the process of melting, the temperature remains constant, and crystals are characterized by anisotropy. There are crystals and amorphous substances (amorphous solids), while amorphous solids do not have the above characteristics.

Crystals are solids in which the internal plasmas are arranged in three dimensions in a periodic repetitive arrangement, with long-range ordering, and are arranged in a periodic repetitive arrangement. Amorphous solids are solids in which the internal plasmas are not periodically repeated in three dimensions, have near-range ordering, but not long-range ordering. Such as glass.

A solid with an irregular shape. The ****ness of a crystal:uniformity, anisotropy, symmetry, self-limiting. Crystals can be divided into four categories according to their structural particles and forces: ionic crystals, atomic crystals, molecular crystals and metal crystals. Solids can be divided into three main categories: crystalline, amorphous, and quasicrystalline.

Solid substances with neat and regular geometric shape, fixed melting point and anisotropy are a basic form of material existence. Whether a solid substance is crystalline or not can generally be identified by X-ray diffraction.

The internal structure of a crystal consists of a lattice of atoms, ions, molecules, and clusters of atoms, which are arranged periodically in three dimensions to form a lattice of a certain form, and a geometric polyhedron of a certain shape.

The planes of a certain geometric polyhedron are called crystal planes, and due to different growth conditions, the crystal may be a little skewed in shape, but the angle between the crystal planes of the same kind of crystal is certain, known as the principle of invariance of the angle of the crystal planes.

Crystals can be categorized into seven major crystal systems and 14 lattice types according to their internal structure. Crystals have a certain symmetry, there are 32 kinds of symmetry element system, the corresponding symmetry action group is called the crystal system point group.

In accordance with the different nature of the force between the internal plasmas, crystals can be divided into ionic crystals, atomic crystals, molecular crystals, metal crystals and other four typical crystals, such as salt, diamond, dry ice and various metals. The same crystal also has a single crystal and polycrystalline (or powder crystal) difference. In practice there are also mixed crystals.

When it comes to crystals, we still have to talk about crystallization. As you know, all matter is made up of atoms or molecules. It is well known that matter comes in three aggregated forms: gases, liquids and solids. However, do you know that solids can be divided into several categories according to their internal structure characteristics? Research has shown that solids can be divided into three main categories: crystalline, amorphous and quasicrystalline.

Crystals usually take on a regular geometric shape, as if someone has deliberately worked them out. The arrangement of the atoms inside them is very regular and strict, much neater than a soldier's square. If you move any atom in a crystal a certain distance in a certain direction, you will find an identical atom.

In contrast, glass, pearls, asphalt, plastics, and other non-crystals, the internal arrangement of atoms is haphazard. Quasicrystals are a new class of substances discovered whose internal arrangement is different from that of both crystals and amorphous crystals.

What kind of substances can be considered crystals? First, with the exception of liquid crystals, crystals are generally in solid form. Second, a substance is crystalline if the atoms, molecules, or ions that make up the substance are arranged in a regular, periodic pattern.