Strontium Element Information, Facts, Properties, Trends, Uses, Comparison with other elements
Strontium is a chemical element with symbol Sr and atomic number 38. An Alkaline Earth Metal, strontium is a soft silver-white or yellowish metallic element that is highly reactive chemically. The metal turns yellow when it is exposed to air.
It belongs to group 2 of the periodic table having trivial name alkaline earth metals*. You can also download Printable Periodic Table of Elements Flashcards for Strontium in a PDF format.
Strontium Facts
Read key information and facts about element Strontium
| Name | Strontium |
| Atomic Number | 38 |
| Atomic Symbol | Sr |
| Atomic Weight | 87.62 |
| Phase | Solid |
| Color | Silver |
| Appearance | - |
| Classification | Alkaline Earth Metal |
| Natural Occurance | Primordial |
| Group in Periodic Table | 2 |
| Group Name | beryllium family |
| Period in Periodic Table | period 5 |
| Block in Periodic Table | s-block |
| Electronic Configuration | [Kr] 5s2 |
| Electronic Shell Structure (Electrons per shell) | 2, 8, 18, 8, 2 |
| Melting Point | 1050 K |
| Boiling Point | 1655 K |
| CAS Number | CAS7440-24-6 |
How to Locate Strontium 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 38 to find Strontium 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 Strontium on periodic table look for cross section of group 2 and period 5 in the modern periodic table.
Strontium History
The element Strontium was discovered by W. Cruikshank in year 1787 in United Kingdom. Strontium was first isolated by H. Davy in 1808. Strontium derived its name from Strontian, a small town in Scotland.
| Discovered By | W. Cruikshank |
| Discovery Date | 1787 in United Kingdom |
| First Isolation | 1808 |
| Isolated by | H. Davy |
Cruikshank and Adair Crawfordin 1790 concluded that strontianite contained a new earth. It was eventually isolated electrochemically in 1808 by Humphry Davy.
Strontium Uses
Strontium is used in pyrotechnics to produce brilliant reds. It can also be used in ferrite magnet production and zinc refining.
Strontium Presence: Abundance in Nature and Around Us
The table below shows the abundance of Strontium 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 Universe | 40 | 0.6 |
| Abundance in Sun | 50 | 0.7 |
| Abundance in Meteorites | 8900 | 2000 |
| Abundance in Earth's Crust | 360000 | 85000 |
| Abundance in Oceans | 8100 | 570 |
| Abundance in Humans | 4600 | 330 |
Crystal Structure of Strontium
The solid state structure of Strontium is Face Centered Cubic.
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)
| a | b | c |
|---|---|---|
| 608.49 pm | 608.49 pm | 608.49 pm |
and the angles between them Lattice Angles (alpha, beta and gamma).
| alpha | beta | gamma |
|---|---|---|
| π/2 | π/2 | π/2 |
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 Name | Fm_ 3m |
| Space Group Number | 225 |
| Crystal Structure | Face Centered Cubic |
| Number of atoms per unit cell | 4 |
The number of atoms per unit cell in a simple cubic, face-centered cubic and body-centred cubic are 1,4,2 respectively.
Strontium Atomic and Orbital Properties
Strontium atoms have 38 electrons and the electronic shell structure is [2, 8, 18, 8, 2] with Atomic Term Symbol (Quantum Numbers) 1S0.
| Atomic Number | 38 |
| Number of Electrons (with no charge) | 38 |
| Number of Protons | 38 |
| Mass Number | 88 |
| Number of Neutrons | 50 |
| Shell structure (Electrons per energy level) | 2, 8, 18, 8, 2 |
| Electron Configuration | [Kr] 5s2 |
| Valence Electrons | 5s2 |
| Valence (Valency) | 2 |
| Main Oxidation States | 2 |
| Oxidation States | 1, 2 |
| Atomic Term Symbol (Quantum Numbers) | 1S0 |
Bohr Atomic Model of Strontium - Electrons per energy level
| n | s | p | d | f |
|---|
Ground State Electronic Configuration of Strontium - neutral Strontium atom
Abbreviated electronic configuration of Strontium
The ground state abbreviated electronic configuration of Neutral Strontium atom is [Kr] 5s2. The portion of Strontium configuration that is equivalent to the noble gas of the preceding period, is abbreviated as [Kr]. 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 5s2, electrons in the outermost shell that determine the chemical properties of the element.
Unabbreviated electronic configuration of neutral Strontium
Complete ground state electronic configuration for the Strontium atom, Unabbreviated electronic configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 5s2
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.
Atomic Structure of Strontium
Strontium atomic radius is 219 pm, while it's covalent radius is 192 pm.
| Atomic Radius Calculated | 219 pm(2.19 Å) |
| Atomic Radius Empirical | 200 pm (2 Å) |
| Atomic Volume | 33.94 cm3/mol |
| Covalent Radius | 192 pm (1.92 Å) |
| Van der Waals Radius | 249 pm |
| Neutron Cross Section | 1.2 |
| Neutron Mass Absorption | 0.0005 |
Spectral Lines of Strontium - Atomic Spectrum of Strontium
A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identify atoms and molecules.
Spectral lines are the result of interaction between a quantum system and a single photon. A spectral line may be observed either as an emission line or an absorption line.
Spectral lines are highly atom-specific, and can be used to identify the chemical composition of any medium. Several elements, including helium, thallium, and caesium, were discovered by spectroscopic means. They are widely used to determine the physical conditions of stars and other celestial bodies that cannot be analyzed by other means.
Emission spectrum of Strontium
Absorption spectrum of Strontium
Strontium Chemical Properties: Strontium Ionization Energies and electron affinity
The electron affinity of Strontium is 5.03 kJ/mol.
| Valence | 2 |
| Electronegativity | 0.95 |
| ElectronAffinity | 5.03 kJ/mol |
Ionization Energy of Strontium
Ionization energy is the amount of energy required to remove an electron from an atom or molecule.in chemistry, this energy is expresed in kilocalories per mole (kcal/mol) or kilojoules per mole (kJ/mol).
Refer to table below for Ionization energies of Strontium
| Ionization energy number | Enthalpy - kJ/mol |
|---|---|
| 1st | 549.5 |
| 2nd | 1064.2 |
| 3rd | 4138 |
| 4th | 5500 |
| 5th | 6910 |
| 6th | 8760 |
| 7th | 10230 |
| 8th | 11800 |
| 9th | 15600 |
| 10th | 17100 |
| 11th | 31270 |
Strontium Physical Properties
Refer to below table for Strontium Physical Properties
| Density | 2.63 g/cm3(when liquid at m.p density is $6.98 g/cm3) |
| Molar Volume | 33.94 cm3/mol |
Elastic Properties
| Young Modulus | - |
| Shear Modulus | 6.1 GPa |
| Bulk Modulus | - |
| Poisson Ratio | 0.28 |
Hardness of Strontium - Tests to Measure of Hardness of Element
| Mohs Hardness | 1.5 MPa |
| Vickers Hardness | - |
| Brinell Hardness | - |
Strontium Electrical Properties
Electrical resistivity measures element's electrical resistance or how strongly it resists electric current.The SI unit of electrical resistivity is the ohm-metre (Ω⋅m). While Electrical conductivity is the reciprocal of electrical resistivity. It represents a element's ability to conduct electric current. The SI unit of electrical conductivity is siemens per metre (S/m).
Strontium is a conductor of electricity. Refer to table below for the Electrical properties of Strontium
| Electrical conductors | Conductor |
| Electrical Conductivity | 7700000 S/m |
| Resistivity | 1.3e-7 m Ω |
| Superconducting Point | - |
Strontium Heat and Conduction Properties
| Thermal Conductivity | 35 W/(m K) |
| Thermal Expansion | 0.0000225 /K |
Strontium Magnetic Properties
| Magnetic Type | Paramagnetic |
| Curie Point | - |
| Mass Magnetic Susceptibility | 1.32e-9 m3/kg |
| Molar Magnetic Susceptibility | 1.16e-10 m3/mol |
| Volume Magnetic Susceptibility | 0.00000347 |
Optical Properties of Strontium
| Refractive Index | - |
Acoustic Properties of Strontium
| Speed of Sound | - |
Strontium Thermal Properties - Enthalpies and thermodynamics
Refer to table below for Thermal properties of Strontium
| Melting Point | 1050 K(776.85 °C, 1430.330 °F) |
| Boiling Point | 1655 K(1381.85 °C, 2519.330 °F) |
| Critical Temperature | - |
| Superconducting Point | - |
Enthalpies of Strontium
| Heat of Fusion | 8 kJ/mol |
| Heat of Vaporization | 137 kJ/mol |
| Heat of Combustion | - |
Strontium Isotopes - Nuclear Properties of Strontium
Strontium has 33 isotopes, with between 73 and 105 nucleons. Strontium has 4 stable naturally occuring isotopes.
Isotopes of Strontium - Naturally occurring stable Isotopes: 84Sr, 86Sr, 87Sr, 88Sr.
| Isotope | Z | N | Isotope Mass | % Abundance | T half | Decay Mode |
|---|---|---|---|---|---|---|
| 73Sr | 38 | 35 | 73 | Synthetic | ||
| 74Sr | 38 | 36 | 74 | Synthetic | ||
| 75Sr | 38 | 37 | 75 | Synthetic | ||
| 76Sr | 38 | 38 | 76 | Synthetic | ||
| 77Sr | 38 | 39 | 77 | Synthetic | ||
| 78Sr | 38 | 40 | 78 | Synthetic | ||
| 79Sr | 38 | 41 | 79 | Synthetic | ||
| 80Sr | 38 | 42 | 80 | Synthetic | ||
| 81Sr | 38 | 43 | 81 | Synthetic | ||
| 82Sr | 38 | 44 | 82 | Synthetic | ||
| 83Sr | 38 | 45 | 83 | Synthetic | ||
| 84Sr | 38 | 46 | 84 | 0.56% | Stable | N/A |
| 85Sr | 38 | 47 | 85 | Synthetic | ||
| 86Sr | 38 | 48 | 86 | 9.86% | Stable | N/A |
| 87Sr | 38 | 49 | 87 | 7% | Stable | N/A |
| 88Sr | 38 | 50 | 88 | 82.58% | Stable | |
| 89Sr | 38 | 51 | 89 | Synthetic | ||
| 90Sr | 38 | 52 | 90 | Synthetic | ||
| 91Sr | 38 | 53 | 91 | Synthetic | ||
| 92Sr | 38 | 54 | 92 | Synthetic | ||
| 93Sr | 38 | 55 | 93 | Synthetic | ||
| 94Sr | 38 | 56 | 94 | Synthetic | ||
| 95Sr | 38 | 57 | 95 | Synthetic | ||
| 96Sr | 38 | 58 | 96 | Synthetic | ||
| 97Sr | 38 | 59 | 97 | Synthetic | ||
| 98Sr | 38 | 60 | 98 | Synthetic | ||
| 99Sr | 38 | 61 | 99 | Synthetic | ||
| 100Sr | 38 | 62 | 100 | Synthetic | ||
| 101Sr | 38 | 63 | 101 | Synthetic | ||
| 102Sr | 38 | 64 | 102 | Synthetic | ||
| 103Sr | 38 | 65 | 103 | Synthetic | ||
| 104Sr | 38 | 66 | 104 | Synthetic | ||
| 105Sr | 38 | 67 | 105 | Synthetic |
Regulatory and Health - Health and Safety Parameters and Guidelines
The United States Department of Transportation (DOT) identifies hazard class of all dangerous elements/goods/commodities either by its class (or division) number or name. The DOT has divided these materials into nine different categories, known as Hazard Classes.
| DOT Numbers | 1383 |
| DOT Hazard Class | 4.2 |
NFPA 704 is a Standard System for the Identification of the Hazards of Materials for Emergency Response. NFPA is a standard maintained by the US based National Fire Protection Association.
The health (blue), flammability (red), and reactivity (yellow) rating all use a numbering scale ranging from 0 to 4. A value of zero means that the element poses no hazard; a rating of four indicates extreme danger.
| NFPA Fire Rating | N/A | N/A |
| NFPA Health Rating | N/A | N/A |
| NFPA Reactivity Rating | N/A | N/A |
| NFPA Hazards | N/A |
| Autoignition Point | - |
| Flashpoint | - |
Database Search
List of unique identifiers to search the element in various chemical registry databases
| Database | Identifier number |
|---|---|
| CAS Number - Chemical Abstracts Service (CAS) | CAS7440-24-6 |
| RTECS Number | - |
| CID Number | CID5359327 |
| Gmelin Number | - |
| NSC Number | - |
Compare Strontium with other elements
Compare Strontium with Group 2, Period 5 and Alkaline Earth Metal elements of the periodic table.
Compare Strontium with all Group 2 elements
Compare Strontium with all Period 5 elements
Compare Strontium with all Alkaline Earth Metal elements
Frequently Asked Questions (FAQ)
Find the answers to the most frequently asked questions about Strontium