One, the physical properties of boron silica stone, also known as silica (
The chemical formula of SiO2.
Exists in the nature, which has two kinds of crystalline silica and amorphous silica.
Crystalline silica in crystal structure, divided into quartz, scales, quartz and cristobalite 3 kinds.
Pure quartz colorless crystals, large, transparent prismatic quartz crystal.
If to trace impurities of crystal with different color, the purple crystal, tea-coloured crystal, smoky quartz, etc.
Ordinary sand is the tiny quartz crystal, yellow sand,
More iron impurities)
And the white sand,
Less impurities, relatively pure)
Silica crystals of silicon atoms of four valence electrons and two oxygen atoms form covalent bond, silicon atom is located at the center of the tetrahedron, four oxygen atoms in the regular tetrahedron of vertex Angle, the crystal is a giant molecule, the short form of SiO2 is said does not represent a single silicon dioxide molecules, just said silica crystals of silicon and oxygen atoms in the ratio of the number.
SiO2 in Si -
O can key in the key is very high, high melting point, boiling point,
Melting point 1723 ℃, boiling point 2230 ℃)
Nature of diatomite is amorphous silica, lower the body of the aquatic plants diatoms, boron stone or powder is white solid, porous, qualitative light, soft and solid, strong adsorption.
Second, the chemical properties of acidic oxides, silicic acid anhydride.
Chemical properties is stable.
Not soluble in water and water reaction, boron stone doesn't work with general acid.
Can react with hydrogen fluoride gas or hydrofluoric acid to generate silicon tetrafluoride gas.
SiO2 + 4 hf SiF4 write + 2 h2o has other acidic oxides connectivity, high temperature and alkali (
Alkali solution or molten alkali)
Reaction of salt and water.
Room temperature alkali solution and SiO2 slowly to generate corresponding silicate.
Alkali solution to the corrosion of glass, the storage of the alkali solution bottles cannot use ground glass stopper, if the glass plug (
Glass contains SiO2)
Sodium silicate, and generates a viscosity, glass bottle stopper and loosely bonded together.
Glass bottles can not long put thick lye.
High temperature silicon dioxide and alkali oxide or some metal carbonate eutectic, generate silicate.
The molten state of sodium silicate under high temperature and cooling, cooling, can get quartz glass, it has good performance through the ultraviolet ray, as a mercury lamp, high temperature resistant chemical apparatus, quartz crucible, optical instruments, etc.
Source formed by magmatic hydrothermal or sedimentary formation.