Strontium

Strontium, ₃₈Sr

Strontium
Pronunciation	/ˈstrɒntiəm/ (listenⓘ) (STRON-tee-əm) /ˈstrɒnʃiəm/ (listenⓘ) (STRON-shee-əm)
Appearance	silvery white metallic; with a pale yellow tint[1]
Standard atomic weight Ar°(Sr)
	87.62(1)[2]
Strontium in the periodic table
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson Ca ↑ Sr ↓ Ba rubidium ← strontium → yttrium
Atomic number (Z)	38
Group	group 2 (alkaline earth metals)
Period	period 5
Block	s-block
Electron configuration	[Kr] 5s2
Electrons per shell	2, 8, 18, 8, 2[3]
Physical properties
Phase at STP	solid
Melting point	1050 K ​(777 °C, ​1431 °F)
Boiling point	1650 K ​(1377 °C, ​2511 °F)
Density (near r.t.)	2.64 g/cm3
when liquid (at m.p.)	2.375 g/cm3
Heat of fusion	7.43 kJ/mol
Heat of vaporization	141 kJ/mol
Molar heat capacity	26.4 J/(mol·K)
Vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 796 882 990 1139 1345 1646
Atomic properties
Oxidation states	+1,[4] +2 (a strongly basic oxide)
Electronegativity	Pauling scale: 0.95
Ionization energies	1st: 549.5 kJ/mol 2nd: 1064.2 kJ/mol 3rd: 4138 kJ/mol
Atomic radius	empirical: 215 pm
Covalent radius	195±10 pm
Van der Waals radius	249 pm
Spectral lines of strontium
Other properties
Natural occurrence	primordial
Crystal structure	​face-centered cubic (fcc)
Thermal expansion	22.5 µm/(m⋅K) (at 25 °C)
Thermal conductivity	35.4 W/(m⋅K)
Electrical resistivity	132 nΩ⋅m (at 20 °C)
Magnetic ordering	paramagnetic
Molar magnetic susceptibility	−92.0×10−6 cm3/mol (298 K)[5]
Young's modulus	15.7 GPa
Shear modulus	6.03 GPa
Poisson ratio	0.28
Mohs hardness	1.5
CAS Number	7440-24-6
History
Naming	after the mineral strontianite, itself named after Strontian, Scotland
Discovery	William Cruickshank (1787)
First isolation	Humphry Davy (1808)
Isotopes of strontium v e
Main isotopes[6] Decay abun­dance half-life (t1/2) mode pro­duct 82Sr synth 25.36 d ε 82Rb 83Sr synth 1.35 d ε 83Rb β+ 83Rb γ – 84Sr 0.56% stable 85Sr synth 64.84 d ε 85Rb γ – 86Sr 9.86% stable 87Sr 7% stable 88Sr 82.6% stable 89Sr synth 50.52 d β− 89Y 90Sr trace 28.90 y β− 90Y
Category: Strontium view talk edit | references

Strontium is a chemical element. It has the chemical symbol Sr. It has the atomic number 38. It is a metal. The color of the metal is silver-white or yellow-silver. The metal is soft, and highly reactive chemically.

In chemistry it is placed in a group of metal elements named the alkaline earth metals. Strontium has a high chemical reactivity. The metal turns yellow when exposed to air. Strontium has properties similar to those of its two vertical neighbors in the periodic table, calcium and barium.

It is found naturally in the minerals celestite and strontianite. The ⁹⁰Sr isotope is present in radioactive fallout and has a half-life of 28.9 years.

Strontium forms salts which make a red flame when they burn. They are used in flares for signalling the position of survivors or shipwrecks and to make the red color in fireworks. It is named after the village of Strontian, Scotland.

Wikimedia Commons has media related to Strontium.

The Simple English Wiktionary has a definition for: strontium.

This short article about chemistry can be made longer. You can help Wikipedia by adding to it.

1. ↑ Greenwood and Earnshaw, p. 112
2. ↑ "Standard Atomic Weights: Strontium". CIAAW. 1969.
3. ↑ "Periodic Table of Elements: Strontium - Sr (EnvironmentalChemistry.com)". environmentalchemistry.com. Retrieved 7 December 2022.
4. ↑ Colarusso, P.; Guo, B.; Zhang, K.-Q.; Bernath, P. F. (1996). "High-Resolution Infrared Emission Spectrum of Strontium Monofluoride" (PDF). J. Molecular Spectroscopy. 175 (1): 158. Bibcode:1996JMoSp.175..158C. doi:10.1006/jmsp.1996.0019.
5. ↑ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
6. ↑ Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.