Strontium Chloride Structure Properties and Applications

Strontium chloride is described as a salt of strontium and chloride. Strontium chloride formula is given as SrCl2. It is defined as a typical strontium chloride salt by forming neutral aqueous solutions. Similar to all the compounds of Sr, this salt also emits a bright red colour in a flame; and, in fact, it can be used as a source of redness in preparing fireworks. The chemical properties of this compound are intermediate between those for barium chloride, which is much toxic, and calcium chloride.

Structure of Strontium Chloride

The crystalline solid of strontium chloride adopts fluorite like structure. In the vapour phase, the SrCl2 molecule is represented as a non-linear having the Cl-Sr-Cl angle of approximately 130°. This is considered as an exception to the VSEPR theory, which predicts a linear structure. Also, the Ab initio calculations have been cited for proposing that contributions from the d orbitals present in the shell below the valence shell are completely responsible. Another proposal is that the electron core polarisation of the strontium atom causes a sort of distortion of the core electron density that directly interacts with the Sr-Cl bonds.

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Properties of Strontium Chloride

Let us look at the important properties of strontium chloride, given as follows:

Physical Properties of Strontium Chloride – SrCl₂

Chemical Properties of Strontium Chloride –  SrCl2

• Strontium chloride compound reacts with fluorine gas resulting in the formation of chlorine gas and strontium fluoride.

SrCl2 (aq) + 2HF (gas) → SrF2 (solid) + Cl2 (gas)

• Strontium chloride also reacts with sulfuric acid by forming hydrogen chloride and strontium hydrogen sulphate.

SrCl2 + 2H2SO4 → Sr(HSO4)2 + 2HCl

Preparation of Strontium Chloride

Strontium chloride is prepared by treating either strontium carbonate or aqueous strontium hydroxide with hydrochloric acid. The chemical reaction for this can be given as follows:

Sr(OH)2 + 2 HCl → SrCl2 + 2 H2O

Crystallization from the cold aqueous solution produces the hexahydrate, SrCl2·6H2O. Dehydration of this salt takes place in stages, commencing above 61 °C (otherwise 142 °F). Full dehydration takes place at 320 °C (otherwise 608 °F).

Uses of Strontium Chloride

Strontium chloride is defined as the precursor to the other strontium compounds, such as strontium carbonate, strontium sulfate, and yellow strontium chromate. Also, the exposure of strontium chloride to the sodium salt of the desired anion (alternately called carbon dioxide gas to produce carbonate) leads to the precipitation of salt. The chemical reactions are given below:

SrCl2 + Na2CO3 → SrCO3 + 2 NaCl

SrCl2 + Na2CrO4 → SrCrO4 + 2 NaCl

SrCl2 + Na2SO4 → SrSO4 + 2 NaCl

SrCl2 + H2O + CO2 → SrCO3 + 2 HCl

Often, strontium chloride can be used as a red colouring agent in pyrotechnics. It also imparts a more intense red colour to the flames compared to most of the other alternatives. It can be employed in very small quantities, metallurgy and glass-making. The radioactive isotope, which is strontium-89, can be used for bone cancer treatment and is usually administered in the strontium chloride form. And, seawater aquaria need small amounts of strontium chloride, which can be consumed during the growth of particular plankton.

Applications of Strontium Chloride

Biological Research

Brief exposure of strontium chloride induces the parthenogenetic activation of the oocytes, which can be used in developmental biological research.

Dental Care

SrCl2 can also be useful in reducing the tooth sensitivity by producing a barrier over the microscopic tubules in the dentin that contain nerve endings which have become exposed by the recession of gum. In the U.S., it is known as Sensodyne and Elecol, and these products are known as "strontium chloride "tubes of toothpaste, although, at present, most use saltpetre (KNO3) instead which works as an analgesic rather than the barrier.

Ammonium Storage

A strontium chloride-based artificial solid is used by a commercial company, called AdAmmine as a means to store the ammonium compound at low pressure, primarily for use in NOx emission reduction on vehicles, that runs by Diesel. They also claim that their patented material is made from a few other salts, but they have chosen this strontium chloride compound for mass production.

Also, the earlier company research considered the stored ammonium as a means to store the synthetic Ammonium fuel compound under the trademark of HydrAmmine and the press name as "hydrogen tablet." However, this particular aspect has not been commercialized. Their materials and processes are patented. And, their early experiments are achieved using magnesium chloride.

Side Effects of Strontium Chloride

Strontium is a silvery metal, which is naturally found as a non-radioactive element. Up to 99 per cent of the strontium present in the human body is concentrated in the bones.

Different forms of strontium metal can be used as medicine. Also, scientists are testing this strontium ranelate metal to see if it can intake through the mouth to treat thinning bones (otherwise osteoporosis) and arthritis.