The quaternary compounds They are all those that have four different atoms or ions. Therefore, they can be molecular or ionic species. Their diversities include both organic and inorganic chemistry, being a very voluminous group; although perhaps not so much compared to binary or ternary compounds.
The reason that their number is smaller is because the four atoms or ions must be held together by their chemical affinities. Not all the elements are compatible with each other, and even less when a quartet is considered; suddenly a pair of them are more akin to each other than to the other pair.
Consider a quaternary compound of the random formula ABCD. The subscripts n, m, p and y are the stoichiometric coefficients, which in turn indicate what proportion of each atom there is in relation to the others..
Thus, the formula AnBmCpDY it will be valid if it complies with electroneutrality. Furthermore, such a compound will be possible if its four atoms are sufficiently related to each other. It will be seen that this formula does not apply to many compounds, but especially to alloys or minerals..
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A quaternary compound can be ionic or covalent, exhibiting the characteristics expected for its nature. Ionic ABCD compounds are expected to be soluble in water, alcohols, or other polar solvents; they should have high boiling and melting points, and be good conductors of electricity when melted.
Regarding the covalent ABCD compounds, most consist of nitrogenous, oxygenated or halogenated organic compounds; that is, its formula would become CnHmORpNY or CnHmORpXY, where X is a halogen atom. Of these molecules it would be logical to think that they were polar, given the high electronegativities of O, N and X.
A purely covalent ABCD compound can have many bonding possibilities: A-B, B-C, D-A, etc., obviously depending on the affinities and electronic capacities of the atoms. Whereas in a purely ionic ABCD compound, its interactions are electrostatic: A+B-C+D-, for example.
In the case of an alloy, considered more of a solid mixture than a compound properly speaking, ABCD consists of neutral atoms in ground states (in theory).
Of the rest, an ABCD compound can be neutral, acidic or basic, depending on the identity of its atoms..
Physically speaking, it is probable that ABCD will not become a gas, since four different atoms always imply a higher molecular mass or formula. If it is not a liquid with a high boiling point, it is to be expected that it is a solid, whose decomposition must generate many products.
Again, their colors, smell, texture, crystals, etc., will be subject to how A, B, C and D coexist in the compound, and will depend on their synergy and structures..
So far, the issue of quaternary compounds has been approached in a global and imprecise way. Leaving aside organic chemistry (amides, benzyl chlorides, quaternary ammonium salts, etc.), in inorganic chemistry there are well-defined examples called acidic and basic oxysalts..
Acid oxysalts are those that derive from the partial neutralization of a polyprotic oxo acid. Thus, one or more of its hydrogens are replaced by metal cations, and the fewer remaining hydrogens it has, the less acidic it will be..
For example, from phosphoric acid, H3PO4, Up to two acid salts of, say, sodium can be obtained. These are: NaHtwoPO4 (Na+ replaces a hydrogen equivalent to H+) and NatwoHPO4.
According to traditional nomenclature, these salts are named in the same way as oxysalts (totally deprotonated), but with the word 'acid' preceding the name of the metal. Thus, the NaHtwoPO4 would be sodium diacid phosphate, and NatwoHPO4 sodium acid phosphate (because it has one H left).
On the other hand, the stock nomenclature prefers to use the word 'hydrogen' than 'acid'. The NaHtwoPO4 would then become sodium dihydrogen phosphate, and NatwoHPO4 sodium hydrogen phosphate. Note that these salts have four atoms: Na, H, P and O.
Basic oxysalts are those that contain the OH anion in their composition-. For example, consider the salt CaNO3OH (Catwo+ NOT3- Oh-). To name it, it would be enough to precede the word 'basic' to the name of the metal. Thus, its name would be: basic calcium nitrate. And how about the CuIO3OH? Its name would be: cupric basic iodate (Cutwo+ IO3- Oh-).
According to the stock nomenclature, the word 'basic' is replaced by hydroxide, followed by the use of a hyphen before the name of the oxoanion.
Repeating the previous examples, their names would be for each one: Calcium hydroxide-nitrate, and copper (II) hydroxide-iodate; remembering that the valence of the metal must be indicated in parentheses and with Roman numerals.
In double salts there are two different cations interacting with the same type of anion. Suppose double salt: Cu3Faith (PO4)3 (Cutwo+ Faith3+ PO43-). It is a phosphate of iron and copper, but the most appropriate name to refer to this is: triple phosphate of copper (II) and iron (III).
These are hydrates, and the only difference is that the number of water to formulate is specified at the end of their names. For example, the MnCltwo is manganese (II) chloride.
Its hydrate, MnCltwo4HtwoOr it is called manganese (II) chloride tetrahydrate. Note that there are four different atoms: Mn, Cl, H and O.
A famous double hydrated salt is Mohr's, Fe (NH4)two(SW4)two6HtwoO. Its name is: double iron (II) sulfate and ammonium hexahydrate.
Again, focusing on inorganic quaternary compounds, it has to be mostly the product of partial neutralizations. If these occur in the presence of several metal oxides, it is likely that double salts will arise; and if the medium is very basic, the basic oxysalts will precipitate.
And if, on the other hand, the water molecules have an affinity for the metal, they will coordinate directly with it or with the ions that surround it, forming the hydrates.
On the alloy side, four different metals or metalloids must be welded to make capacitors, semiconductors or transistors..
Finally, a list with different examples of quaternary compounds is shown below. The reader can use it to test their knowledge of nomenclature:
- PbCO3(OH)two
- Cr (HSO4)3
- NaHCO3
- ZnIOH
- Cutwo(OH)twoSW3
- LitwoKAsO4
- COURSE45HtwoOR
- AgAu (SO4)two
- Case42HtwoOR
- FeCl36HtwoOR
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