The barium peroxide is an ionic and inorganic compound whose chemical formula is BaOtwo. Being an ionic compound, it consists of Ba ionstwo+ metwotwo-; the latter is what is known as the peroxide anion, and because of it BaOtwo acquires its name. This being the case, the BaOtwo is an inorganic peroxide.
The charges of its ions reveal how this compound is formed from the elements. The group 2 barium metal gives two electrons to the oxygen molecule, Otwo, whose atoms are not used to reduce themselves to oxide anions, ORtwo-, but to be held together by a simple link, [O-O]two-.
Barium peroxide is a granular solid at room temperature, white with slight grayish hues (upper image). Like almost all peroxides, it must be handled and stored with care, as it can accelerate the oxidation of certain substances.
Of all the peroxides formed by group 2 metals (Mr. Becambara), BaOtwo it is thermodynamically the most stable against its thermal decomposition. When heated, it releases oxygen and barium oxide, BaO, is produced. BaO can react with oxygen in the environment, at high pressures, to form BaO againtwo.
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The upper image shows the tetragonal unit cell of barium peroxide. Inside it can be seen the cations Batwo+ (white spheres), and the anions Otwotwo- (red spheres). Note that the red spheres are joined by a single bond, so they represent linear geometry [O-O]two-.
From this unit cell, BaO crystals can be builttwo. If observed, the anion Otwotwo- it is seen to be surrounded by six Batwo+, obtaining an octahedron whose vertices are white.
On the other hand, even more evident, each Batwo+ is surrounded by ten Otwotwo- (white sphere in the center). All crystal consists of this constant short and long range order.
If the red white spheres are also observed, it will be noted that they do not differ too much in their sizes or ionic radii. This is because the Ba cationtwo+ is very bulky, and its interactions with the anion Otwotwo- stabilize the lattice energy of the crystal to a better degree compared to how, for example, Ca cations wouldtwo+ and Mgtwo+.
This also explains why BaO is the most unstable of the alkaline earth oxides: Ba ions.two+ metwo- differ considerably in size, destabilizing their crystals.
As it is more unstable, the lower is the trend of BaOtwo decomposing to form BaO; contrary to peroxides SrOtwo, CaOtwo and MgOtwo, whose oxides are more stable.
The BaOtwo can be found in the form of hydrates, of which BaOtwo∙ 8HtwoOr it is the most stable of all; and in fact, this is the one that is marketed, instead of the anhydrous barium peroxide. To obtain the anhydrous one, the BaO must be dried at 350 ° Ctwo∙ 8HtwoOr, for the purpose of removing the water.
Its crystal structure is also tetragonal, but with eight molecules of HtwoO interacting with the Otwotwo- through hydrogen bonds, and with the Batwo+ by dipole-ion interactions.
Other hydrates, of whose structures there is not much information in this regard, are: BaOtwo∙ 10HtwoO, BaOtwo∙ 7HtwoO and BaOtwo∙ HtwoOR.
The direct preparation of barium peroxide consists of the oxidation of its oxide. This can be used from the mineral barite, or from the barium nitrate salt, Ba (NO3)two; both are heated in an air or oxygen-enriched atmosphere.
Another method consists of reacting Ba (NO3)two with sodium peroxide:
Bath3)two + NatwoORtwo + xHtwoO => BaOtwo∙ xHtwoO + 2NaNO3
Then the hydrate BaOtwo∙ xHtwoOr it is subjected to heating, filtered and finished by drying using vacuum.
It is a white solid that can turn grayish if it has impurities (either BaO, Ba (OH)two, or other chemical species). If it is heated to a very high temperature, it will give off greenish flames, due to the electronic transitions of the Ba cations.two+.
169.33 g / mol.
5.68 g / mL.
450 ° C.
800 ° C. This value agrees with what should be expected of an ionic compound; and even more, of the most stable alkaline earth peroxide. However, the BaO does not really boiltwo, rather, gaseous oxygen is released as a result of its thermal decomposition.
Insoluble. However, it can slowly undergo hydrolysis to produce hydrogen peroxide, HtwoORtwo; and furthermore, its solubility in aqueous medium increases if a dilute acid is added.
The following chemical equation shows the thermal decomposition reaction that BaO undergoestwo:
2BaOtwo <=> 2BaO + Otwo
The reaction is one-way if the temperature is above 800 ° C. If the pressure is immediately increased and the temperature decreases, all the BaO will be transformed back into BaOtwo.
Another way to name the BaOtwo it is barium peroxide, according to the traditional nomenclature; since barium can only have the valence +2 in its compounds.
Erroneously, the systematic nomenclature is used to refer to it as barium dioxide (binoxide), considering it an oxide and not a peroxide.
Using the mineral barite (BaO), it is heated with currents of air to eliminate its oxygen content, at a temperature of around 700 ° C..
If the resulting peroxide is gently heated under vacuum, the oxygen is regenerated more quickly and the barite can be reused indefinitely to store and produce oxygen..
This process was commercially devised by L. D. Brin, now obsolete.
Barium peroxide reacts with sulfuric acid to produce hydrogen peroxide:
Beamtwo + HtwoSW4 => HtwoORtwo + Basso4
It is therefore a source of HtwoORtwo, manipulated especially with its hydrate BaOtwo∙ 8HtwoOR.
According to these two uses mentioned, the BaOtwo allows the development of Otwo and HtwoORtwo, both oxidizing agents, in organic synthesis and in bleaching processes in the textile and dye industries. It is also a good disinfecting agent..
Furthermore, from BaOtwo other peroxides can be synthesized, such as sodium, NatwoORtwo, and other barium salts.
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