What temperature does a crystal have and what is the definition of a crystal?

Crystals have a definite melting (solidifying) temperature.

Crystal is a structure in which a large number of microscopic material units (atoms, ions, molecules, etc.) are arranged in an orderly manner, so the arrangement rules and crystal morphology can be judged from the size of the structural units.

Features. (1) The crystals formed by natural condensation and without external interference have neat and regular geometric shapes, that is, the self-normity of the crystals.

2) Crystals have a fixed melting point, and the temperature remains constant during the melting process.

3) Single crystals are anisotropic.

4) Crystals can cause regular diffraction of X-rays.

Whether X-ray diffraction can be produced on a macroscopic scale is the main method for determining whether a substance is a crystal or not.

5) The crystals correspond to the equal angles of the crystal planes, which is called the conservation of the crystal plane angles.

Crystal is a substance formed by the regular periodic repetition of the particles (molecules, atoms, ions) of a substance in three-dimensional space.

From a macroscopic point of view, crystals have their own unique and symmetrical shapes, such as table salt in the form of cubes; Ice is hexagonal prism; Alum is octahedral, etc. Crystals have different physical properties in different directions, such as mechanical strength, thermal conductivity, thermal expansion, electrical conductivity, etc., which are called anisotropy.

Introduction to crystals. The particles (atoms, ions, molecules, and clusters) in the internal structure of the crystal are regularly and repeatedly arranged in three-dimensional space to form a certain form of crystal lattice, which is a geometric polyhedron of a certain shape. The plane that composes a certain geometric polyhedron is called the crystal plane, due to the 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, which is called the principle of invariant crystal plane angle.

The theoretical crystallization temperature refers to the fact that each substance has a certain equilibrium crystallization temperature.

Crystallization temperature refers to the temperature required by the process of transformation of a substance from a liquid to a crystal. However, in practice, crystallization cannot be carried out when the temperature of the liquid reaches the theoretical crystallization temperature, and the shed must be destroyed at a certain temperature below its temperature before it begins to crystallize.

In the actual crystallization process, the actual crystallization temperature is always lower than the theoretical crystallization temperature, and the fiber sum becomes a supercooling phenomenon, and the temperature difference between the two is called supercooling.

The theoretical crystallization temperature refers to the fact that each substance has a certain equilibrium crystallization temperature.

The crystallization temperature refers to the Xiaodan temperature required for the process of transforming a substance from a liquid to a crystal. However, in practice, crystallization cannot occur when the liquid temperature reaches the theoretical crystallization temperature, and crystallization must begin at a certain temperature below its temperature.

In the actual crystallization process, the actual crystallization temperature is always lower than the theoretical crystallization temperature, and this phenomenon becomes the supercooling phenomenon, and the temperature difference between the two is called the supercooling degree.

Crystal: It is a closed structure with a large number of microscopic material units arranged in an orderly manner according to a certain rule, so the arrangement rules and crystal morphology can be judged from the size of the structural units.

Crystals can be divided into four categories according to their structure, particles and forces: ionic crystals, atomic crystals, molecular crystals and metal crystals. Solids can be divided into three categories: crystalline, amorphous, and quasicrystalline.

A solid substance with a neat and regular geometry, a fixed melting point, and anisotropy is a basic form of the existence of matter. Whether a solid substance is a crystalline body can generally be determined by X-ray diffraction.