Strontium metal. Properties strontium. Application strontium

Atom number 38 with a mass of 87.62. In nature, it is found in a stable state in the form of 4 isotopes: 84, 86, 87, 88. The most common 88 in nature. In connection with the decay of natural rubidium 87, the exact amount of strontium changes over time. A person was obtained radioactive atoms with numbers 80-97.

Moreover, the most frequently used isotope was obtained from uranium - Strontium 90.. The history of the discovery of the element leaves the distant 90s of the eighteenth century. Back in 1787, Strontsia was first isolated from Strontsianit Mineral near Strontian village in Scotland.

The first studies conducted academic chemists Ader Crawford and Martin Henry Clapot. In Russia, Strontician land research was conducted by Tobiasov Falls. A distinctive characteristic was the burning of a bright red flame.

Stronticia description and properties

Strontium formula - Sr. It is a polymorphic metal white painting with silver tide. Due to the rapid reaction in pure form with an oxygen oxide film with a yellow tint. Strontium Metal Very soft and easily sufficient forging.

Presented in three modifications: a cubic grazent crystalline grille - up to 231 ° C, hexagonal - from 231 to 623 ° C, cubic volume-centered - at temperatures above 623 ° C. Atom strontium It has the structure of the external electronic shell 5S2. The reactions are oxidized and takes shape +2, sometimes + 1. Structure atom strontium: 1S2 2S2 2P6 3S2 3P6 3D10 4S2 4P6 5S2

Basic physical indicators:

Atomic volume - 34 cm 3 / g × atom;

Radius of an atom - 2.15 A;

Density - 2.63 g / cm 3 at 20 ° C;

TPL. \u003d 770 ° C;

TKIP. \u003d 1380 ° C;

UD. heat-stage 0.176 cal / g × hail at 20 ° C;

Pressure of steam 10-3 mm mercury pillar at 462 ° C, 1 mM Mercury column 733 ° C and 100 mm Mercury pillar at 1092 ° C;

Surface tension 165 din / cm;

Brinell hardness 13 kg / mm2;

Chemical characteristic strontium. According to the reactivity of strontium close to its brothers about the Barium and Calcium group. Under normal conditions, quickly interacts with atmospheric air oxygen. Forms oxide strontium Sro and sro 2 with a yellowish tint.

Like all alkaline earth metals reacts with water - forms hydroxide strontium. Interaction with halogens is very active - halides are formed. The powdered form of metal is very quickly flammable even at room temperature and atmospheric pressure.

Especially important at the same time are iodide and chloride strontium. When heated, it is actively connected to carbon dioxide, carbonate and hydrocarbonate is formed. In the gas phase, the hydride SRH 2 is formed by adding hydrogen. The following compounds are also most common: carbon-based carbide - carbon-based compounds (SRC 2), amide - with ammonia in gaseous state (SR (NH 2) 2), sulfide - with gray (SRS), selenide - with selenium (SRSE) and some Others.

Strontium in molten state It is easily mixed with metals such as aluminum, iron, barium, and others. There is a homogenization of the melt with obtaining intermetallic. Strontsia easily reacts with diluted acids. A huge number of varied salts is obtained in reactions with organic and mineral acids.

However, showing high reactivity with weak acids, with concentrated, on the contrary, does not show activity. Therefore, sulfates, nitrates, nitrites and others salt strontium Received in reactions with dilute acids. The bulk of salts are painted in white with varying degrees of solubility in water (based on mineral acids, as a rule, dissolve better).

Characteristic strontium as a radioactive element. Radioactive isotope is obtained in nuclear reactors for β - -Repad Rubidia 90, after which the strontium passes the stage β --asset to obtain a nuclide of yttrium 90. Half-life strontium equal to 28.79 years.

Departure and mining strontium

Strontsia is widespread in nature. The element in the form of ore lies in the earth's crust. In the World Ocean there is more than 24% of the total element stock. Natural reserves exists only in the associated state and are minerals, the total number of which has no less than 40. In the land of the CIS countries, Western Europe, North America, mainly in Canada, found the largest ore deposits: strontium - strontium carbonate and - strontium sulfat.

Industrial methods for producing metal are based on the processing of mineral ores by various connections. After that, thermal decomposition of the compounds or electrolytic effects are carried out. However, as a result of such reactions, a powdered metal form is formed, which is very easily flammable, or the output of the element is very low and obtained with impurities. Therefore, currently the above methods are not used.

The restoration of strontium oxide remains the most popular with the addition of metal aluminum and flint sand. The reaction passes in a vacuum tube made of steel at very high temperatures above 1,000 ° C. The cleaning of the element is also carried out by distillation also under vacuum. For atomic energy, it is extremely important to obtain radioactive isotopes.

They are obtained in reactors during the uranium half-life 235. Isotope SR 89 ( polispad strontium 50.5 days) is formed after decay with the allocation of a huge amount of energy from stable isotope. Strontium is an indispensable part of the animal and plant world. Many organisms accumulate an element in themselves with calcium and phosphorus.

Application strontium

Metal is used as a doping agent. Adds hardness and plasticity. In the mixture with baryium and calcium are explosive. It is part of thermal mixtures.

Using strontium compounds:

SRO is a piece of oxide cathodes, pyrotechnic mixtures.

SRCO 3 - Get special coatings - chemistry and thermal glaze.

SR (NO 3) 2 is a component of pyrotechnic substances for signal missiles.

SRSO 4 - filler for paints and rubber.

SrCro 4 is the component of varnishes and primers in the aircraft industry.

SRTIO 3 - material production of dielectric antennas, conductors and sensors.

SRF 2 is used in the production of specialized.

SRCL 2 is a component of pyrotechnic compositions, cosmetics and medical drugs.

SRS is used in the production of additives in the manufacture of skin.

90 Strontium 137. Cezium is used as a component of radioactive fuel.

The most useful substance based on organic compounds - stronging Ranlant. - Bone growth stimulator. This drug is carried out with osteoporosis.

Price strontium

Metal strontium is most often sold in the form of connections. Prices connections strontium It varies widely: nitrate - 3.8 USD, chloride - 500-800 rubles, ranks in the form of drugs from 1500 to 2500 rubles.