Fr Element

2 7

👆🏻

Block

s block

Element Family

Alkali

CAS Number

7440735

Rank: 18 (Overall)

7429905 54386242

👆🏻

Space Group Name

Space Group Number

225.00

Rank: 3 (Overall)

11 276

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Facts

Interesting Facts

223 Francium has the longest half life at 21.8.
Francium metal is produced by alpha decay in ²²⁷Actinium 227.

Sources

Formed by Decay Process, Mining

History

Who Discovered

Marguerite Perey

Discovery

In 1939

Abundance

Abundance In Universe

0.00 %

Rank: 40 (Overall)

0 0.11

👆🏻

Abundance In Sun

0.00 %

Rank: 30 (Overall)

0 0.1

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Abundance In Meteorites

0.00 %

76% - Alkali Metals Metals

0 22

👆🏻

Abundance In Earth's Crust

0.00 %

Rank: 60 (Overall)

1E-37 8.1

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Abundance In Oceans

0 1.1

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Abundance In Humans

0.00 %

Rank: 24 (Overall)

0 1.4

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Uses

Uses & Benefits

Francium has no known uses as it has a half life of only 22 minutes.

Industrial Uses

Medical Uses

Other Uses

Biological Properties

Toxicity

Present in Human Body

✔ ✘

In Blood

0.00 Blood/mg dm-3

Rank: 40 (Overall)

0 1970

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In Bone

0.00 p.p.m.

Rank: 41 (Overall)

0 170000

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Physical

Melting Point

27.00 °C

-38.83 3410

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Boiling Point

677.00 °C

Rank: 78 (Overall)

0 5660

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Appearance

Physical State

Solid

Color

Luster

Hardness

Mohs Hardness

0.20

Rank: 27 (Overall)

0.2 8.5

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Brinell Hardness

119.00 MPa

Rank: 59 (Overall)

0.14 3490

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Vickers Hardness

300.00 MPa

Rank: 46 (Overall)

0 3920

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Speed of Sound

2,440.00 m/s

8% - Alkali Metals Metals

818 16200

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Optical Properties

Refractive Index

1.70

Rank: 27 (Overall)

0.155 3.41

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Reflectivity

72.00 %

Rank: 11 (Overall)

5 97

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Allotropes

✔ ✘

α Allotropes

β Allotropes

γ Allotropes

Chemical

Chemical Formula

Isotopes

Known Isotopes

Rank: 6 (Overall)

0 38

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Electronegativity

Pauling Electronegativity

0.70

0 2.6

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Sanderson Electronegativity

0.70

Rank: 47 (Overall)

0.22 2.56

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Allred Rochow Electronegativity

0.86

Rank: 42 (Overall)

0.86 1.9

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Mulliken-Jaffe Electronegativity

0.68

0.62 2.48

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Allen Electronegativity

0.67

Rank: 67 (Overall)

0.659 2.7

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Electropositivity

Pauling Electropositivity

3.30

1.46 3.3

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Ionization Energies

1st Energy Level

380.00 kJ/mol

Rank: 89 (Overall)

375.7 26130

👆🏻

2nd Energy Level

392.80 kJ/mol

Rank: 85 (Overall)

392.8 28750

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3rd Energy Level

392.80 kJ/mol

392.8 34230

👆🏻

4th Energy Level

392.80 kJ/mol

Rank: 86 (Overall)

375.7 37066

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5th Energy Level

392.00 kJ/mol

392 97510

👆🏻

6th Energy Level

3,920.00 kJ/mol

1007 105800

👆🏻

7th Energy level

3,920.00 kJ/mol

1007 114300

👆🏻

8th Energy Level

3,920.00 kJ/mol

Rank: 80 (Overall)

730 125300

👆🏻

9th Energy Level

3,920.00 kJ/mol

Rank: 82 (Overall)

1007 134700

👆🏻

10th Energy Level

392.00 kJ/mol

392 144300

👆🏻

11th Energy Level

392.00 kJ/mol

392 169988

👆🏻

12th Energy Level

38,000.00 kJ/mol

Rank: 23 (Overall)

0 189368

👆🏻

13th Energy Level

3,920.00 kJ/mol

Rank: 80 (Overall)

1007 76015

👆🏻

14th Energy Level

380.00 kJ/mol

380 86450

👆🏻

15th Energy Level

67,700.00 kJ/mol

Rank: 32 (Overall)

33000 100700

👆🏻

16th Energy Level

39,200.00 kJ/mol

Rank: 66 (Overall)

375.7 109480

👆🏻

17th Energy Level

392.00 kJ/mol

375.7 122200

👆🏻

18th Energy Level

3,920.00 kJ/mol

Rank: 78 (Overall)

0 134810

👆🏻

19th Energy Level

392.80 kJ/mol

375.7 148700

👆🏻

20th Energy Level

392.00 kJ/mol

0 171200

👆🏻

21st Energy Level

392.00 kJ/mol

Rank: 90 (Overall)

375.7 179100

👆🏻

22nd Energy Level

392.00 kJ/mol

Rank: 75 (Overall)

330 184900

👆🏻

23rd Energy Level

392.80 kJ/mol

Rank: 86 (Overall)

357.6 198800

👆🏻

24th Energy Level

392.00 kJ/mol

Rank: 87 (Overall)

297.3 195200

👆🏻

25th Energy Level

392.00 kJ/mol

Rank: 79 (Overall)

0 121900

👆🏻

26th Energy Level

392.80 kJ/mol

Rank: 87 (Overall)

357.6 127700

👆🏻

27th Energy Level

392.00 kJ/mol

Rank: 83 (Overall)

0 133800

👆🏻

28th Energy Level

380.00 kJ/mol

Rank: 86 (Overall)

297.3 139800

👆🏻

29th Energy Level

392.00 kJ/mol

0 148100

👆🏻

30th Energy Level

677.00 kJ/mol

0 154500

👆🏻

Electrochemical Equivalent

8.32 g/amp-hr

0.16812 8.3209

👆🏻

Electron Work Function

4.07 eV

Rank: 33 (Overall)

2.14 6

👆🏻

Other Chemical Properties

Ionization, Radioactive Isotopes, Radioactivity, Solubility

Atomic

Atomic Number

3 117

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Electron Configuration

[Rn] 7s¹

Crystal Structure

Body Centered Cubic (BCC)

Crystal Lattice

Atom

Number of Protons

3 117

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Number of Neutrons

136

Rank: 18 (Overall)

4 285

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Number of Electrons

3 117

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Radius of an Atom

Atomic Radius

348.00 pm

0 348

👆🏻

Covalent Radius

260.00 pm

0 260

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Van der Waals Radius

348.00 pm