Rubidium

Rubidium
Rubidium block | Image: Learnool

Rubidium (Rb) is a chemical element of the periodic table, located in group 1 and period 5, and has the atomic number 37. It is a very soft, silvery-white alkali metal whose name comes from the Latin word “rubidus” (which means the deepest red). It was discovered in 1861 by Robert Bunsen and Gustav Kirchhoff, who observed its spectral lines while studying the emission spectra of various elements.

Rubidium and cesium are utilized interchangeably or simultaneously in many applications due to their similar physical properties and atomic radii. However, cesium has a higher electropositivity than rubidium, making it a more suitable material for particular applications. One to two metric tons of rubidium is sold in the United States each year, which is a very small market.[1] Its primary application is in specialty glasses used in fiber optic telecommunication systems.

On periodic table

group 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
period
1 1
H
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Hydrogen
2
He
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Helium
2 3
Li
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Lithium
4
Be
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Beryllium
5
B
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Boron
6
C
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Carbon
7
N
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Nitrogen
8
O
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Oxygen
9
F
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Fluorine
10
Ne
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Neon
3 11
Na
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Sodium
12
Mg
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Magnesium
13
Al
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Aluminium
14
Si
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Silicon
15
P
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Phosphorus
16
S
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Sulfur
17
Cl
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Chlorine
18
Ar
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Argon
4 19
K
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Potassium
20
Ca
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Calcium
21
Sc
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Scandium
22
Ti
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Titanium
23
V
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Vanadium
24
Cr
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Chromium
25
Mn
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Manganese
26
Fe
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Iron
27
Co
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Cobalt
28
Ni
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Nickel
29
Cu
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Copper
30
Zn
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Zinc
31
Ga
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Gallium
32
Ge
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Germanium
33
As
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Arsenic
34
Se
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Selenium
35
Br
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Bromine
36
Kr
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Krypton
5 37
Rb
Rubidium
38
Sr
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Strontium
39
Y
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Yttrium
40
Zr
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Zirconium
41
Nb
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Niobium
42
Mo
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Molybdenum
43
Tc
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Technetium
44
Ru
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Ruthenium
45
Rh
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Rhodium
46
Pd
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Palladium
47
Ag
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Silver
48
Cd
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Cadmium
49
In
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Indium
50
Sn
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Tin
51
Sb
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Antimony
52
Te
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Tellurium
53
I
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Iodine
54
Xe
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Xenon
6 55
Cs
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Caesium
56
Ba
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Barium
72
Hf
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Hafnium
73
Ta
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Tantalum
74
W
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Tungsten
75
Re
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Rhenium
76
Os
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Osmium
77
Ir
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Iridium
78
Pt
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Platinum
79
Au
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Gold
80
Hg
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Mercury
81
Tl
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Thallium
82
Pb
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Lead
83
Bi
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Bismuth
84
Po
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Polonium
85
At
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Astatine
86
Rn
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Radon
7 87
Fr
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Francium
88
Ra
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Radium
104
Rf
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Rutherfordium
105
Db
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Dubnium
106
Sg
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Seaborgium
107
Bh
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Bohrium
108
Hs
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Hassium
109
Mt
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Meitnerium
110
Ds
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Darmstadtium
111
Rg
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Roentgenium
112
Cn
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Copernicium
113
Nh
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Nihonium
114
Fl
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Flerovium
115
Mc
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Moscovium
116
Lv
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Livermorium
117
Ts
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Tennessine
118
Og
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Oganesson
57
La
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Lanthanum
58
Ce
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Cerium
59
Pr
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Praseodymium
60
Nd
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Neodymium
61
Pm
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Promethium
62
Sm
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Samarium
63
Eu
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Europium
64
Gd
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Gadolinium
65
Tb
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Terbium
66
Dy
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Dysprosium
67
Ho
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Holmium
68
Er
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Erbium
69
Tm
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Thulium
70
Yb
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Ytterbium
71
Lu
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Lutetium
89
Ac
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Actinium
90
Th
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Thorium
91
Pa
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Protactinium
92
U
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Uranium
93
Np
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Neptunium
94
Pu
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Plutonium
95
Am
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Americium
96
Cm
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Curium
97
Bk
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Berkelium
98
Cf
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Californium
99
Es
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Einsteinium
100
Fm
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Fermium
101
Md
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Mendelevium
102
No
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Nobelium
103
Lr
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Lawrencium
– s block

Rubidium is an s-block element, situated in the first column of the periodic table, below potassium (K). It has the atomic number 37 and is denoted by the symbol Rb.

Element information

Rubidium Element
Rubidium appearance | Image: Wikipedia
Rubidium Periodic Table
Rubidium location on periodic table | Image: Learnool
Rubidium is found in the first column of the periodic table below the potassium element.
Origin of name Latin word “rubidus” (which means the deepest red)
Symbol Rb
Atomic number (Z) 37
Atomic mass 85.4678 u
Block s-block
Group 1
Period 5
Classification Alkali metal
Atomic radius 248 pm
Covalent radius 220±9 pm
Van der Waals radius 303 pm
Melting point 39.30 ℃, 102.74 ℉, 312.45 K
Boiling point 688 ℃, 1270 ℉, 961 K
Electron configuration [Kr] 5s1
Electrons per shell 2, 8, 18, 8, 1
Crystal structure Body-centered cubic (bcc)
Phase at r.t Solid
Density near r.t 1.532 g/cm3
Main isotopes Rubidium-85
Natural occurrence Primordial
Oxidation state +1
Electronegativity (Pauling scale) 0.82
Protons
Neutrons
Electrons
37
48
37
Valence electrons 1
Learn how to find: Rubidium valence electrons
CAS number 7440-17-7
Discovered by Robert Bunsen and Gustav Kirchhoff in 1861

History

Gustav Kirchhoff (left) and Robert Bunsen | Image: Science History Institute

Rubidium was discovered in 1861 at Heidelberg, Germany, by Robert Bunsen and Gustav Kirchhoff while examining the mineral lepidolite using flame spectroscopy. Its name is derived from the color of the two prominent lines in the red portion of the element’s spectrum.[2]

Rubidium was the second element found via spectroscopy, immediately after cesium, just one year after Bunsen and Kirchhoff invented the spectroscope. It had almost no industrial uses until the 1920s, when small amounts were utilized in photoelectric cells. Since then, much of the rubidium consumed has been utilized in various types of research.

Occurrence and production

In the Earth’s crust, natural rubidium makes up roughly 0.01 percent. It is more abundant than some popular metals like copper, lead, and zinc, all of which are mined at quantities measured in the millions of metric tonnes per year, as compared to rubidium’s possible global mining quantity of perhaps 2 to 4 tonnes per year. Rubidium can be found naturally in minerals such as leucite, pollucite, carnallite, and zinnwaldite. Some potassium rocks and brines also contain considerable amounts of the element.

Rubidium is difficult to produce in pure form because it naturally occurs alongside cesium and other alkali metals. Hence, pure rubidium must be extracted from its ores lepidolite and pollucite and then separated from potassium and cesium through a series of chemical processes. Methods like fractional crystallization, chlorostannate process, and ferrocyanide process have been used to extract rubidium.

Properties

Rubidium interacts violently with water, just like other alkali metals do. Additionally, it has been noted that rubidium can spontaneously burn in the air.

The metal quickly reacts with water and produces a colorless solution of rubidium hydroxide RbOH and hydrogen gas H2. It produces rubidium monoxide Rb2O when exposed to air and superoxide RbO2 when exposed to too much oxygen.

Rubidium's Purple Color Flame
Rubidium’s purple color flame | Image: Wikipedia

Rubidium, like potassium, exhibits a very similar purple color in the flame test.

Naturally occurring rubidium has two isotopes with atomic weights of 85 and 87, which occur in amounts around 72.2% and 27.8% by weight. 87Rb has a half-life of 48.8 billion years and is radioactive.

Other rubidium isotopes, which are all very radioactive and have few uses, have been synthesized artificially.

Applications

In vacuum tubes, rubidium is utilized as a getter, a substance that mixes with and extracts trace gasses from vacuum tubes.

Rubidium is utilized in fiber optic telecommunication systems, specialty glasses, night vision devices, and other applications.

It is used in electronic device manufacturing and as a frequency reference in atomic clocks.

Additionally, it is utilized in the rubidium-strontium dating method, a radiometric dating technique, which is employed by scientists to determine the age of rocks and minerals. The decay of radioactive 87Rb and 86Sr has been widely used to determine the age of rocks and minerals.

Rubidium Burns With A Purple Hue When Used In Pyrotechnics
Rubidium burns with a purple hue when used in pyrotechnics | Image: Thermo Fisher Scientific

Rubidium compounds are sometimes employed in fireworks to give them a purple tint.

For positron emission tomography (PET) scans, rubidium-82 is employed.

In terms of mood, anti-conservative beliefs, work, occupational interests, and psychomotor slowness, rubidium chloride showed a marked and quick anti-depressive action.[3]

Rubidium can be quickly ionized, making it a potential propellant for ion engines on spacecraft.

Interesting facts

Rubidium has a density higher than water, and so it does not float on water.

Rubidium was discovered using a flame emission spectroscopy method.

It is the second most electropositive element among stable alkali metals.

Rubidium is the twenty-second most abundant element on earth.

Rubidium melts just above the body temperature, at 39.30 ℃.

Rubidium ignites in the air and reacts violently with water, so it is kept in mineral oil.

Related

More elements

s block
p block
d block
f block
Barium Aluminium Bohrium Actinium
Beryllium Antimony Cadmium Americium
Caesium Argon Chromium Berkelium
Calcium Arsenic Cobalt Californium
Francium Astatine Copernicium Cerium
Helium Bismuth Copper Curium
Hydrogen Boron Darmstadtium Dysprosium
Lithium Bromine Dubnium Einsteinium
Magnesium Carbon Gold Erbium
Potassium Chlorine Hafnium Europium
Radium Flerovium Hassium Fermium
Rubidium Fluorine Iridium Gadolinium
Sodium Gallium Iron Holmium
Strontium Germanium Lawrencium Lanthanum
Indium Lutetium Mendelevium
Iodine Manganese Neodymium
Krypton Meitnerium Neptunium
Lead Mercury Nobelium
Livermorium Molybdenum Plutonium
Moscovium Nickel Praseodymium
Neon Niobium Promethium
Nihonium Osmium Protactinium
Nitrogen Palladium Samarium
Oganesson Platinum Terbium
Oxygen Rhenium Thorium
Phosphorus Rhodium Thulium
Polonium Roentgenium Uranium
Radon Ruthenium Ytterbium
Selenium Rutherfordium
Silicon Scandium
Sulfur Seaborgium
Tellurium Silver
Tennessine Tantalum
Thallium Technetium
Tin Titanium
Xenon Tungsten
Vanadium
Yttrium
Zinc
Zirconium

References

1. Mineral Commodity Profiles – Rubidium

2. C&EN: IT’S ELEMENTAL: THE PERIODIC TABLE – RUBIDIUM

3. Rubidium chloride in the treatment of major depression

External links

Deep

Learnool.com was founded by Deep Rana, who is a mechanical engineer by profession and a blogger by passion. He has a good conceptual knowledge on different educational topics and he provides the same on this website. He loves to learn something new everyday and believes that the best utilization of free time is developing a new skill.

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