Periodic table

 

 

Atomic number:5

Group numbers:13

Period:2

Electronic configuration:[He] 2s² 2p¹

Formal oxidation number:+3

Electronegativities:2.04

Atomic radius / pm:79.5

Relative atomic mass:10.811 ± 0.007

 

Boron compounds have been known for thousands of years, but the element was not discovered until 1808 by Sir Humphry Davy (GB) and independently by Joseph-Louis Gay-Lussac and Louis-Jaques Thénard (FR). The origin of the name comes from the Arabic word buraq and the Persian word burah meaning boraks (Na2B4O7*10H2O). It is hard, brittle, lustrous black semimetal. Boron is unreactive with oxygen, water, alkalis or acids. It combines with most metals to form borides. Boron is obtained from kernite, a kind of borax (Na2B4O7*10H2O). High purity boron is produced by electrolysis of molten potassium fluroborate and potassium chloride (KCl). Amorphous boron is used in pyrotechnic flares to provide a distinctive green colour and in rockets as an igniter.

PHYSICAL PROPERTIES

Density / g dm^-3:2340 (beta, 293 K)

Molar volume / cm³mol^-1:4.62 (beta, 293 K)

Electrical resistivity / μΩcm:1.8E+12 (20 °C)

THERMAL PROPERTIES

Thermal conductivity / W m^-1K^-1:27

Melting point / °C:2075

Boiling point / °C:4000

Heat of fusion / kJ mol^-1:22.2

Heat of vaporization / kJ mol^-1:504.5

Heat of atomization / kJ mol^-1:557.64

IONIZATION ENERGIES

First ionization energy / kJ mol^-1:800.64

Second ionization energy / kJ mol^-1:2427.09

Third ionization energy / kJ mol^-1:3659.78

ABUNDANCE OF ELEMENTS

in the atmosphere / ppm:-

in the Earth's crust / ppm:10

in the oceans / ppm:4.8

CRYSTALLOGRAPHIC DATA

ISOTOPES

REDUCTION POTENTIALS

 

Scientific calculator for chemists
Download printable materials	|   |	Free software for Windows
Periodic Table of the Elements

 

Citing this page:

Generalic, Eni. "Boron." EniG. Periodic Table of the Elements. 16 May 2013. KTF-Split. {Date of access}. <http://www.periodni.com/b.html>.