Category

Boron

Catalogue

Atomic structure
Discovery
Source
Element USES
physical property
Chemical property
Geological data
Biology data

Atomic structure

Atomic radius/Å: 1.17
Atomic volume/cm3 / mol: 4.6
Covalent radius/A: 0.82
Electronic configuration: 1 2 s2p1 s2
Ion radius/Å: 0.23
Oxidation state: III

Discovery

In 1808, Paris, France's L.J. Lussac and L.J. Thenard Humphry Davy and London found Mr.

Source

From kernite get, namely borax (Na2B4O7 · 10 H2O).

Element USES

And titanium tungsten light resistance alloy system together, also used for thermal glass manufacturing, and the preparation of the eyes disinfection.

physical property

State: yellow brown non-metallic crystals. Melting point (℃) : 2300
Boiling point (℃) : 4002
Density (g/cc, 300 K) : 2.34

Than hot/J/gK: 1.02
Evaporation heat/KJ/mol: 489.7
Melting hot/KJ/mol: 50.2

Conductive rate / 106 / cm: 1.0 E-12
Coefficient of thermal conductivity/W/cmK: 0.274

Geological data

abundance
Retention time/year: 1 x 107

The sun (relative to the H = 1 x 1012) : 2.63 by 105
Sea/P.P.M. : 4.41

The earth's crust/P.P.M. : 950

Biology data

Content in the human body
Liver/P.P.M. : 0.4-3.3
Organs:
Muscle/P.P.M. : 0.33 1
Blood/mg dm-3:0.13
Th intake/mg: 1-3
Bone/P.P.M. : 1.1-3.3
People (70 Kg) are total body/mg: 18

Detailed information

B, atomic number 5, atomic weight 10.811. About 200 BC, Roman, ancient Egypt, Babylon used to make glass and welding boron sand gold. In 1808, French chemist cover · he and the Tate's lu respectively with metal potassium reduction of boron boric acid reacts. B in the earth's crust of the content is 0.001%. There are two kinds of natural boron isotope: boron 10 and 11 boron, of which the most important boron 10.

For solid boron in silver or black. Crystal boron is black, melting point about 2300 ° C, boiling point 2550 ° C, density of 2.34 g/cm ³, hardness is second only to the diamond, brittle.

Boron in room temperature is stable, even in the medium and long term hydrofluoric acid hydrochloric acid or boil doesn't work. B can and marinated group elements directly combined, form halogenating boron. B in 600 ~ 1000 ° C and sulfur, tin, phosphorus, arsenic response; In 1000 ~ 1400 ° C and nitrogen, carbon, silicon effect, high temperature with many metal and boron metal oxide reaction, forming metal boron carbide. These compounds is usually high hardness, resistance to melt, high conductivity and chemical inert substance, often with special properties.

The application of boron is more extensive. B and plastic or aluminum alloy combination is effective neutron shielding materials; Boron in steel in the reactor used for bar; Boron fiber used in the manufacture of composite materials, etc.