~晶体的常识(2)

Whether the microscopic particle periodic orderly arranged in three-dimensional space
Observation ·Thinking
Ask someone to determine the following crystalline or noncrystalline substance is :
Para
Diamond
Snowflake
Diatomite
Alum
Salt
Foam
Crystal
Crystals from one of the conditions of plastic is appropriate growth rate
Natural crystal ball agate and crystal
Agate is rapidly cooled molten SiO2 formed - no rules outline Crystal is slowly cooled molten SiO2 formed - a regular shape
First of all, let us together to enjoy some beautiful crystal
Rock candy
Diamond
Crystal
wk.baidu.com
Graphite
Crystalline and amorphous
1.The definition :
Crystal: material particles (molecules, atoms and ions) in three dimensional space formed by the regular periodic arrangement of the material.
Common crystals : alum , salt (NaCl), monosodium glutamate , copper sulfate , diamond , ice, and so on. amorphous : beeswax , glass, rosin , asphalt , rubber , wax, plastic,and so on.
Crystals
Have
Anisotr opy
Fixed
Amorph ous
Does not have a regular geometric shape
Particle relatively disordered arrangeme No nt
Isotrop ic
Not fixed
Essential difference
projection diagram of Crystalline SiO2 and amorphous SiO2
Crystals
Amorphous
Atoms are arranged periodically orderly
Atoms are arranged relatively disordered
Amorphous
Amorphous: amorphous refers to the material composition of molecules (or atoms and ions) is not a space solid rules periodically. It does not have the appearance of a certain rules
< 1 >. Regular geometric shape - self-limitation property The crystal particle orderly cyclical repetition - essential characteristics < 2 >. The anisotropy (electrical conductivity, thermal conductivity, optical properties, etc.)
From the copper sulfate precipitation in saturated solution of copper sulfate crystals
4 . To identify the crystal and amorphous
Five Features
Distinguish between crystal and amorphous most reliable scientific methods are: solid for X-ray diffraction experiments
<3>Homogeneity (Crystal chemical composition, density and other properties of the crystal are the same) < 4 >. Crystal has a fixed melting point < 5 >. Symmetry (crystal shape and internal structure have symmetry. In shape, there is often an equal crystal, edge and vertex Angle repeated)
The common sense of the crystal
-----zhangrui -----fengjuan
The common sense of the crystal
First,The definition of crystalline and amorphous Second, the characteristics of the crystal Third, Crystal formation Fourth,summary
Difference: the crystal particles (atoms, ions or molecules) in space orderly arrangement is according to certain rules to be cyclical.
2.The characteristics of the crystal
The graphite in the direction parallel to the layer of the conductivity is approximately in the direction perpendicular to the layer conductivity 10000 times.
Summary: crystal and amorphous differences Solid Exterior Microstr Since the Aniso Mp plastic tropy ucture
Having a regular geometric shape
Particles in threedimensional space periodically ordered
Sublimation of iodine
Material solidified from the molten state Gaseous materials without liquid cooling
solidification (sublimation) directly Solute precipitated from the solution
Thinking: to get the crystal, as well as the cooling method, and there is no other way? Can you name?
3. Crystal formation
From the molten crystallization sulfur crystals