Mendeleev's Periodic Table > B - Boron

B - Boron

Black amorphous boron powder was isolated from borax by Joseph Louis Gay-Lussac (with Thenard) and independently by Davy in 1808. Hard, red crystals of pure boron were not produced for almost one hundred years.

Atomic number - 5 Density g/mL 2 .34
Atomic weight u 10 .81 Melting point K 2300
Bonding radius A 0 .82 Boiling point K 4275
Atomic radius A 1 .17 Heat of vaporization kJ/mol 489 .7
Ionization Potential V 8 .298 Heat of fusion kJ/mol 50 .2
Electronegativity - 2 .04 Specific heat J/gK 1 .02
The oxide is mildly acidic. Crystal are rhombohedral.
Electron config. : 1s2 2s2 2p1

Isotopes of B (Boron):

MASS abundancy
Halflife
Particle, Energy
Decay Product(s)
Isotopic Mass		 007
1.4 MeV
2p/3p/p,2.200
Li-5/He-4/Be-6
7.0299196 		008
770 msec
EC/EC2a/ECa,18.071
Be-8/none/He-4
8.0246067 		009
0.54KEV
2a/p,11.941
H-1/Be-8
9.0133289 		010 19.9%

Stable

10.012937
MASS abundancy
Halflife
Particle, Energy
Decay Product(s)
Isotopic Mass		 011 80.1%

Stable

11.009305 		012
20.20 msec
B-/B-3a,13.369
C-12/none
12.014352 		013
17.36 msec
B-,13.437 MeV
C-13
13.017780 		014
13.8 msec
B-,20.644 MeV
C-14
14.025404
MASS abundancy
Halflife
Particle, Energy
Decay Product(s)
Isotopic Mass		 015
10.5 msec
B-,19.094 MeV
C-15
15.031097 		016

n,1.480 MeV
B-15
16.039828 		017
5.08 msec
B-,22.680 MeV
C-17
17.046935