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B Boron
Element Information, Facts, Properties, Trends, Uses, Comparison with other elements

5
B
Boron
Element 5 of Periodic table is Boron with atomic number 5, atomic weight 10.811. Boron, symbol B, has a Simple Trigonal structure and Black color. Boron is a Metalloid element. It is part of group 13 (boron family). Know everything about Boron Facts, Physical Properties, Chemical Properties, Electronic configuration, Atomic and Crystal Structure.
5 B - Boron | SchoolMyKids

Boron is a Metalloid chemical element with symbol B and atomic number 5. Produced entirely by cosmic ray spallation and supernovae and not by stellar nucleosynthesis, it is a low-abundance element in both the Solar system and the Earth's crust. Boron is concentrated on Earth by the water-solubility of its more common naturally occurring compounds, the borate minerals.

It belongs to group 13 of the periodic table having trivial name triels, icosagens. It got its trivial name from triels from Greek tri (three, III).

Boron Facts

Read key information and facts about element Boron

NameBoron
Atomic Number5
Atomic SymbolB
Atomic Weight10.811
PhaseSolid
ColorBlack
Appearanceblack-brown
ClassificationMetalloid
Group in Periodic Table13
Group Nameboron family
Period in Periodic Tableperiod 2
Block in Periodic Tablep -block
Electronic Configuration[He] 2s2 2p1
Electronic Shell Structure (Electrons per shell)2, 3
Melting Point2348 K
Boiling Point4273 K
CAS NumberCAS7440-42-8
Neighborhood Elements
123456789101112131415161718
1
1
H
Hydrogen
1.008

Atomic #

Electronic Shell #

Symbol
Name
Atomic Weight
HGas
HgLiquid
CSolid
Metals
Metalloids
NonMetals
Alkali metals
Alkali earth metals
Lanthanoids
Transition metals
Post-transition metals
Other nonmetals
Halogens
Nobel gas
Actinoids
2
He
Helium
4.003
2
3
Li
Lithium
6.941
4
Be
Beryllium
9.012
5
B
Boron
10.811
6
C
Carbon
12.011
7
N
Nitrogen
14.007
8
O
Oxygen
15.999
9
F
Fluorine
18.998
10
Ne
Neon
20.180
3
11
Na
Sodium
22.990
12
Mg
Magnesium
24.305
13
Al
Aluminium
26.982
14
Si
Silicon
28.085
15
P
Phosphorus
30.974
16
S
Sulfur
32.065
17
Cl
Chlorine
35.453
18
Ar
Argon
39.948
4
19
K
Potassium
39.098
20
Ca
Calcium
40.078
21
Sc
Scandium
44.956
22
Ti
Titanium
47.867
23
V
Vanadium
50.941
24
Cr
Chromium
51.996
25
Mn
Manganese
54.938
26
Fe
Iron
55.845
27
Co
Cobalt
58.933
28
Ni
Nickel
58.693
29
Cu
Copper
63.546
30
Zn
Zinc
65.409
31
Ga
Gallium
69.723
32
Ge
Germanium
72.640
33
As
Arsenic
74.922
34
Se
Selenium
78.960
35
Br
Bromine
79.904
36
Kr
Krypton
83.798
5
37
Rb
Rubidium
85.468
38
Sr
Strontium
87.620
39
Y
Yttrium
88.906
40
Zr
Zirconium
91.224
41
Nb
Niobium
92.906
42
Mo
Molybdenum
95.940
43
Tc
Technetium
98
44
Ru
Ruthenium
101.070
45
Rh
Rhodium
102.906
46
Pd
Palladium
106.420
47
Ag
Silver
107.868
48
Cd
Cadmium
112.411
49
In
Indium
114.818
50
Sn
Tin
118.710
51
Sb
Antimony
121.760
52
Te
Tellurium
127.600
53
I
Iodine
126.904
54
Xe
Xenon
131.293
6
55
Cs
Cesium
132.905
56
Ba
Barium
137.327
57 - 71
La - Lu
Lanthanides
72
Hf
Hafnium
178.490
73
Ta
Tantalum
180.948
74
W
Tungsten
183.840
75
Re
Rhenium
186.207
76
Os
Osmium
190.230
77
Ir
Iridium
192.217
78
Pt
Platinum
195.078
79
Au
Gold
196.967
80
Hg
Mercury
200.590
81
Tl
Thallium
204.383
82
Pb
Lead
207.200
83
Bi
Bismuth
208.980
84
Po
Polonium
209
85
At
Astatine
210
86
Rn
Radon
222
7
87
Fr
Francium
223
88
Ra
Radium
226
89 - 103
Ac - Lr
Actinides
104
Rf
Rutherfordium
261
105
Db
Dubnium
262
106
Sg
Seaborgium
266
107
Bh
Bohrium
264
108
Hs
Hassium
277
109
Mt
Meitnerium
268
110
Ds
Darmstadtium
281
111
Rg
Roentgenium
272
112
Cn
Copernicium
285
113
Nh
Nihonium
284
114
Fl
Flerovium
289
115
Mc
Moscovium
288
116
Lv
Livermorium
292
117
Ts
Tennessine
294
118
Og
Oganesson
294
Lanthanides
57
La
Lanthanum
138.905
58
Ce
Cerium
140.116
59
Pr
Praseodymium
140.908
60
Nd
Neodymium
144.240
61
Pm
Promethium
145
62
Sm
Samarium
150.360
63
Eu
Europium
151.964
64
Gd
Gadolinium
157.250
65
Tb
Terbium
158.925
66
Dy
Dysprosium
162.500
67
Ho
Holmium
164.930
68
Er
Erbium
167.259
69
Tm
Thulium
168.934
70
Yb
Ytterbium
173.040
71
Lu
Lutetium
174.967
Actinides
89
Ac
Actinium
227
90
Th
Thorium
232.038
91
Pa
Protactinium
231.036
92
U
Uranium
238.029
93
Np
Neptunium
237
94
Pu
Plutonium
244
95
Am
Americium
243
96
Cm
Curium
247
97
Bk
Berkelium
247
98
Cf
Californium
251
99
Es
Einsteinium
252
100
Fm
Fermium
257
101
Md
Mendelevium
258
102
No
Nobelium
259
103
Lr
Lawrencium
262

How to Locate Boron on Periodic Table

Periodic table is arranged by atomic number, number of protons in the nucleus which is same as number of electrons. The atomic number increases from left to right. Periodic table starts at top left ( Atomic number 1) and ends at bottom right (atomic number 118). Therefore you can directly look for atomic number 5 to find Boron on periodic table.

Another way to read periodic table and locate an element is by using group number (column) and period number (row). To locate Boron on periodic table look for cross section of group 13 and period 2 in the modern periodic table.

Boron History

The element Boron was discovered by L. Gay-Lussac and L.J. Thénard in year 1808 in France and United Kingdom. Boron was first isolated by H. Davy in 1808. Boron derived its name from borax, a mineral.

Radical boracique appears on the list of elements in Lavoisier's Traité Élémentaire de Chimie from 1789. On June 21, 1808, Lussac and Thénard announced a new element in sedative salt, Davy announced the isolation of a new substance from boracic acid on June 30.

Boron Presence: Abundance in Nature and Around Us

The table below shows the abundance of Boron in Universe, Sun, Meteorites, Earth's Crust, Oceans and Human Body.

 ppb by weight (1ppb =10^-7 %)ppb by atoms (1ppb =10^-7 %)
Abundance in Universe10.1
Abundance in Sun20.2
Abundance in Meteorites16003000
Abundance in Earth's Crust870017000
Abundance in Oceans44402500
Abundance in Humans700410

Crystal Structure of Boron

The solid state structure of Boron is Simple Trigonal.

The Crystal structure can be described in terms of its unit Cell. The unit Cells repeats itself in three dimensional space to form the structure.

Unit Cell Parameters

The unit cell is represented in terms of its lattice parameters, which are the lengths of the cell edges Lattice Constants (a, b and c)

abc
506 pm506 pm506 pm

and the angles between them Lattice Angles (alpha, beta and gamma).

alphabetagamma
1.01334 1.01334 1.01334

The positions of the atoms inside the unit cell are described by the set of atomic positions ( xi, yi, zi) measured from a reference lattice point.

The symmetry properties of the crystal are described by the concept of space groups. All possible symmetric arrangements of particles in three-dimensional space are described by the 230 space groups (219 distinct types, or 230 if chiral copies are considered distinct.

Space Group NameR_ 3m 5 B Boron - Crystal Structure | SchoolMyKids
Oxidation StatesSpace Group Number166
Crystal StructureSimple Trigonal

Boron Atomic and Orbital Properties

Boron atoms have 5 electrons and the electronic shell structure is [2, 3] with Atomic Term Symbol (Quantum Numbers) 2P1/2.

Atomic Number5
Number of Electrons (with no charge)5
Number of Protons5
Mass Number11
Number of Neutrons6
Shell structure (Electrons per energy level)2, 3
Electron Configuration[He] 2s2 2p1
Valence Electrons2s2 2p1
Valence (Valency)3
Main Oxidation States3
Oxidation States-5, -1, 0, 1, 2, 3
Atomic Term Symbol (Quantum Numbers)2P1/2

Bohr Atomic Model of Boron - Electrons per energy level

5 B Boron - Electron Shell Structure | SchoolMyKids
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Ground State Electronic Configuration of Boron - neutral Boron atom

Abbreviated electronic configuration of Boron

The ground state abbreviated electronic configuration of Neutral Boron atom is [He] 2s2 2p1. The portion of Boron configuration that is equivalent to the noble gas of the preceding period, is abbreviated as [He]. For atoms with many electrons, this notation can become lengthy and so an abbreviated notation is used. This is important as it is the Valence electrons 2s2 2p1, electrons in the outermost shell that determine the chemical properties of the element.

Unabbreviated electronic configuration of neutral Boron

Complete ground state electronic configuration for the Boron atom, Unabbreviated electronic configuration

1s2 2s2 2p1

Electrons are filled in atomic orbitals as per the order determined by the Aufbau principle, Pauli Exclusion Principle and Hund’s Rule.

  • As per the Aufbau principle the electrons will occupy the orbitals having lower energies before occupying higher energy orbitals. According to this principle, electrons are filled in the following order: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p…
  • The Pauli exclusion principle states that a maximum of two electrons, each having opposite spins, can fit in an orbital.
  • Hund's rule states that every orbital in a given subshell is singly occupied by electrons before a second electron is filled in an orbital.
  • Electron configuration of Boron
    Atomic Structure of Boron

    Boron atomic radius is 87 pm, while it's covalent radius is 82 pm.

    Atomic Radius Calculated

    87 pm (0.87 Å)

    Atomic Radius Empirical

    85 pm (0.85 Å)

    Atomic Volume4.3947 cm3/mol
    Covalent Radius82 pm (0.82 Å)
    Van der Waals Radius192 pm
    Neutron Cross Section755
    Neutron Mass Absorption 2.4

    Atomic Spectrum of Boron

    Atomic Spectrum of Boron | SchoolMyKids

    Boron Chemical Properties: Boron Ionization Energies and electron affinity

    The electron affinity of Boron is 26.7 kJ/mol.

    Valence3
    Electronegativity2.04
    ElectronAffinity26.7 kJ/mol

    Ionization Energy of Boron

    Refer to table below for Ionization energies of Boron

    Ionization energy numberEnthalpy - kJ/mol
    1st800.6
    2nd2427.1
    3rd3659.7
    4th25025.8
    5th32826.7

    Boron Physical Properties

    Refer to below table for Boron Physical Properties

    Density2.46 g/cm3(when liquid at m.p density is $2.08 g/cm3)
    Molar Volume4.3947 cm3/mol

    Elastic Properties

    Young Modulus-
    Shear Modulus-
    Bulk Modulus 320 GPa
    Poisson Ratio-

    Hardness of Boron - Tests to Measure of Hardness of Element

    Mohs Hardness9.3 MPa
    Vickers Hardness49000 MPa
    Brinell Hardness-

    Boron Electrical Properties

    Boron is Conductor of electricity. Refer to table below for the Electrical properties ofBoron

    Electrical Conductivity0.0001 S/m
    Resistivity10000 m Ω
    Superconducting Point-

    Boron Heat and Conduction Properties

    Thermal Conductivity27 W/(m K)
    Thermal Expansion0.000006 /K

    Boron Magnetic Properties

    Magnetic TypeDiamagnetic
    Curie Point-
    Mass Magnetic Susceptibility-8.7e-9 m3/kg
    Molar Magnetic Susceptibility-9.41e-11 m3/mol
    Volume Magnetic Susceptibility-0.0000214

    Optical Properties of Boron

    Refractive Index-

    Acoustic Properties of Boron

    Speed of Sound16200 m/s

    Boron Thermal Properties - Enthalpies and thermodynamics

    Refer to table below for Thermal properties of Boron

    Melting Point2348 K (2074.85°C, 3766.7299999999996 °F)
    Boiling Point4273 K (3999.85°C, 7231.7300000000005 °F)
    Critical Temperature-
    Superconducting Point-

    Enthalpies of Boron

    Heat of Fusion50 kJ/mol
    Heat of Vaporization507 kJ/mol
    Heat of Combustion-

    Boron Isotopes - Nuclear Properties of Boron

    Boron has 14 isotopes, with between 6 and 19 nucleons. Boron has 2 stable naturally occuring isotopes.

    Isotopes of Boron - Naturally occurring stable Isotopes: 10B, 11B.

    IsotopeZNIsotope Mass% AbundanceT halfDecay Mode
    6B516Synthetic
    7B527Synthetic
    8B538Synthetic
    9B549Synthetic
    10B551019.9%StableN/A
    11B561180.1%Stable
    12B5712Synthetic
    13B5813Synthetic
    14B5914Synthetic
    15B51015Synthetic
    16B51116Synthetic
    17B51217Synthetic
    18B51318Synthetic
    19B51419Synthetic

    Database Search

    List of unique identifiers to search the element in various chemical registry databases

    DatabaseIdentifier number
    CAS Number - Chemical Abstracts Service (CAS)CAS7440-42-8
    RTECS NumberRTECSED7350000
    CID Number CID5462311
    Gmelin Number-
    NSC Number-