Symbol
Pa
Sr
Group Number
32
0
17
👆🏻
Period Number
75
2
7
👆🏻
Block
f block
s block
Element Family
Actinide
Alkaline Earth
CAS Number
74401337440246
7429905
54386242
👆🏻
Space Group Name
I4/mmm
Fm_ 3m
Space Group Number
139.00225.00
11
276
👆🏻
Interesting Facts
- Protactinium metal has 29 isotopes.
- Isotopes of Protactinium-231 used in nuclear weapon.
- Strontium element is softer than Calcium.
- Silvery Strontium turns yellow, if exposed to air.
Sources
Found in Uranium Ores, Mining, Ores of metals
Found in Minerals, Mining, Ores of Minerals
History
Who Discovered
William Crookes
William Cruickshank
Discovery
In 1900
In 1787
Abundance
Abundance In Universe
0.00 %0.00 %
0
0.11
👆🏻
Abundance In Sun
0.00 %0.00 %
0
0.1
👆🏻
Abundance In Meteorites
-0.00 %
0
22
👆🏻
Abundance In Earth's Crust
0.00 %0.04 %
1E-37
8.1
👆🏻
Abundance In Oceans
0.00 %0.00 %
0
1.1
👆🏻
Abundance In Humans
0.00 %0.00 %
0
1.4
👆🏻
Uses & Benefits
- Currently known uses of Protactinium metal are limited to research purpose only.
- Strontium metal is used to producing ferrite magnets as well as refining zinc.
-
By-product of nuclear reactors called Strontium-90 is a radioactive isotope; it is absorbed by tissues and destroys bone marrow and cancer growth.
Industrial Uses
-
Ammunition Industry, Chemical Industry
Medical Uses
-
-
Other Uses
-
Alloys
Biological Properties
Toxicity
Highly Toxic
Non Toxic
Present in Human Body
✔
✘
✔
✘
In Blood
0.00 Blood/mg dm-30.03 Blood/mg dm-3
0
1970
👆🏻
In Bone
0.00 p.p.m.140.00 p.p.m.
0
170000
👆🏻
Melting Point
1,568.00 °C769.00 °C
-38.83
3410
👆🏻
Boiling Point
4,027.00 °C1,384.00 °C
0
5660
👆🏻
Appearance
Physical State
Solid
Solid
Color
Silver
Silvery White
Luster
Metallic
Metallic
Hardness
Mohs Hardness
5.001.50
0.2
8.5
👆🏻
Brinell Hardness
125.00 MPa110.00 MPa
0.14
3490
👆🏻
Vickers Hardness
220.00 MPa15.00 MPa
0
3920
👆🏻
Speed of Sound
12,400.00 m/s4,170.00 m/s
818
16200
👆🏻
Optical Properties
Refractive Index
1.601.43
0.155
3.41
👆🏻
Reflectivity
60.00 %65.00 %
5
97
👆🏻
Allotropes
✔
✘
✔
✘
α Allotropes
-
-
β Allotropes
-
-
γ Allotropes
-
-
Chemical Formula
Pa
Sr
Isotopes
Known Isotopes
2727
0
38
👆🏻
Electronegativity
Pauling Electronegativity
1.500.95
0
2.6
👆🏻
Sanderson Electronegativity
1.500.72
0.22
2.56
👆🏻
Allred Rochow Electronegativity
1.140.99
0.86
1.9
👆🏻
Mulliken-Jaffe Electronegativity
1.501.00
0.62
2.48
👆🏻
Allen Electronegativity
1.500.96
0.659
2.7
👆🏻
Electropositivity
Pauling Electropositivity
2.503.05
1.46
3.3
👆🏻
Ionization Energies
1st Energy Level
568.00 kJ/mol549.50 kJ/mol
375.7
26130
👆🏻
2nd Energy Level
1,128.00 kJ/mol1,064.20 kJ/mol
392.8
28750
👆🏻
3rd Energy Level
1,814.00 kJ/mol4,138.00 kJ/mol
392.8
34230
👆🏻
4th Energy Level
2,991.00 kJ/mol5,500.00 kJ/mol
375.7
37066
👆🏻
5th Energy Level
5,120.00 kJ/mol6,910.00 kJ/mol
392
97510
👆🏻
6th Energy Level
5,680.00 kJ/mol8,760.00 kJ/mol
1007
105800
👆🏻
7th Energy level
5,680.00 kJ/mol10,230.00 kJ/mol
1007
114300
👆🏻
8th Energy Level
5,680.00 kJ/mol11,800.00 kJ/mol
730
125300
👆🏻
9th Energy Level
5,120.00 kJ/mol15,600.00 kJ/mol
1007
134700
👆🏻
10th Energy Level
5,120.00 kJ/mol17,100.00 kJ/mol
392
144300
👆🏻
11th Energy Level
5,680.00 kJ/mol31,270.00 kJ/mol
392
169988
👆🏻
12th Energy Level
5,680.00 kJ/mol5,490.00 kJ/mol
0
189368
👆🏻
13th Energy Level
5,680.00 kJ/mol5,490.00 kJ/mol
1007
76015
👆🏻
14th Energy Level
5,680.00 kJ/mol5,490.00 kJ/mol
380
86450
👆🏻
15th Energy Level
56,800.00 kJ/mol54,900.00 kJ/mol
33000
100700
👆🏻
16th Energy Level
56,800.00 kJ/mol54,900.00 kJ/mol
375.7
109480
👆🏻
17th Energy Level
568.50 kJ/mol549.50 kJ/mol
375.7
122200
👆🏻
18th Energy Level
5,680.00 kJ/mol5,490.00 kJ/mol
0
134810
👆🏻
19th Energy Level
568.30 kJ/mol549.50 kJ/mol
375.7
148700
👆🏻
20th Energy Level
568.00 kJ/mol549.00 kJ/mol
0
171200
👆🏻
21st Energy Level
568.00 kJ/mol549.50 kJ/mol
375.7
179100
👆🏻
22nd Energy Level
568.00 kJ/mol549.00 kJ/mol
330
184900
👆🏻
23rd Energy Level
568.00 kJ/mol549.50 kJ/mol
357.6
198800
👆🏻
24th Energy Level
568.00 kJ/mol549.50 kJ/mol
297.3
195200
👆🏻
25th Energy Level
568.00 kJ/mol549.00 kJ/mol
0
121900
👆🏻
26th Energy Level
568.00 kJ/mol549.50 kJ/mol
357.6
127700
👆🏻
27th Energy Level
568.00 kJ/mol549.50 kJ/mol
0
133800
👆🏻
28th Energy Level
568.00 kJ/mol549.50 kJ/mol
297.3
139800
👆🏻
29th Energy Level
568.00 kJ/mol549.50 kJ/mol
0
148100
👆🏻
30th Energy Level
568.00 kJ/mol549.50 kJ/mol
0
154500
👆🏻
Electrochemical Equivalent
1.72 g/amp-hr1.64 g/amp-hr
0.16812
8.3209
👆🏻
Electron Work Function
5.89 eV2.59 eV
2.14
6
👆🏻
Other Chemical Properties
Ionization, Radioactive Isotopes, Radioactivity
Ionization, Radioactive Isotopes, Radioactivity, Solubility
Atomic Number
9138
3
117
👆🏻
Electron Configuration
[Rn] 5f2 6d1 7s2
[Kr] 5s2
Crystal Structure
Tetragonal (TETR)
Face Centered Cubic (FCC)
Crystal Lattice
Atom
Number of Protons
9138
3
117
👆🏻
Number of Neutrons
12250
4
285
👆🏻
Number of Electrons
9138
3
117
👆🏻
Radius of an Atom
Atomic Radius
163.00 pm215.00 pm
0
348
👆🏻
Covalent Radius
200.00 pm195.00 pm
0
260
👆🏻
Van der Waals Radius
243.00 pm249.00 pm
0
348
👆🏻
Atomic Weight
231.04 amu87.62 amu
6.94
294
👆🏻
Atomic Volume
15.00 cm3/mol33.70 cm3/mol
1.39
71.07
👆🏻
Adjacent Atomic Numbers
Previous Element
Next Element
Valence Electron Potential
92.00 (-eV)25.70 (-eV)
0
392.42
👆🏻
Lattice Constant
392.50 pm608.49 pm
0
891.25
👆🏻
Lattice Angles
π/2, π/2, π/2
π/2, π/2, π/2
Lattice C/A Ratio
1.581.57
0.423
1.9
👆🏻
Density
Density At Room Temperature
15.37 g/cm32.64 g/cm3
0.534
40.7
👆🏻
Density When Liquid (at m.p.)
15.37 g/cm32.38 g/cm3
0.512
41
👆🏻
Tensile Strength
80.00 MPa170.00 MPa
0.1
11000
👆🏻
Viscosity
0.000.00
1.5E-05
0.0035
👆🏻
Vapor Pressure
Vapor Pressure at 1000 K
0.00 (Pa)121.00 (Pa)
0
121
👆🏻
Vapor Pressure at 2000 K
0.00 (Pa)0.00 (Pa)
0
774
👆🏻
Elasticity properties
Shear Modulus
16.00 GPa6.03 GPa
1.3
222
👆🏻
Bulk Modulus
47.00 GPa11.00 GPa
0
462
👆🏻
Young's Modulus
47.00 GPa15.70 GPa
0
528
👆🏻
Poisson Ratio
0.230.28
0.032
0.47
👆🏻
Other Mechanical Properties
-
-
Magnetic Characteristics
Specific Gravity
15.372.64
0.53
4500
👆🏻
Magnetic Ordering
Paramagnetic
Paramagnetic
Permeability
0.00 H/m0.00 H/m
1.25643E-06
0.0063
👆🏻
Susceptibility
0.000.00
-0.000166
200000
👆🏻
Electrical Properties
Electrical Property
Conductor
-
Resistivity
177.00 nΩ·m132.00 nΩ·m
0.1
961
👆🏻
Electrical Conductivity
0.05 106/cm Ω0.08 106/cm Ω
0
0.63
👆🏻
Electron Affinity
53.03 kJ/mol5.03 kJ/mol
0
222.8
👆🏻
Specific Heat
0.12 J/(kg K)0.30 J/(kg K)
0.1
3.6
👆🏻
Molar Heat Capacity
27.20 J/mol·K26.40 J/mol·K
13.1
62.7
👆🏻
Thermal Conductivity
47.00 W/m·K35.40 W/m·K
0
429
👆🏻
Critical Temperature
1,841.00 K1,050.00 K
26.3
3695
👆🏻
Thermal Expansion
9.90 µm/(m·K)22.50 µm/(m·K)
4.5
97
👆🏻
Enthalpy
Enthalpy of Vaporization
481.00 kJ/mol150.00 kJ/mol
7.32
799.1
👆🏻
Enthalpy of Fusion
12.34 kJ/mol9.16 kJ/mol
2.1
35.23
👆🏻
Enthalpy of Atomization
481.90 kJ/mol163.20 kJ/mol
61.5
837
👆🏻
Standard Molar Entropy
198.10 J/mol.K55.00 J/mol.K
9.5
198.1
👆🏻