- Inorganic chemical functions
- - Oxides
- Metallic or basic oxides
- Acidic oxides or anhydrides
- Neutral oxides
- Mixed oxides
- - You go out
- - Acids
- - Bases
- Organic chemical functions
- Examples of chemical functions
- References
The chemical functions are a number of features that allow to categorize or group a set of compounds, either by its reactivity, structure, solubility, etc. There being inorganic and organic compounds, it is to be expected that their compartments are different and, in the same way, the chemical functions by which they are classified.
It can be said that the chemical functions would become huge families of compounds, within which there are increasingly specific subdivisions. For example, salts represent an inorganic chemical function; but we have hundreds of them, classified as binary, ternary or oxysal and mixed.
Salts represent one of the main chemical functions of inorganic compounds. Source: Yamile via Pexels.
The salts are scattered throughout the hydrosphere and lithosphere, the latter literally harboring mountains of mineral oxides. Therefore, due to their great abundance, oxides correspond to another important inorganic chemical function, also with their internal divisions (basic, acidic and mixed).
On the side of organic compounds, functions are better defined as functional groups, since they are responsible for their chemical properties. Among the most relevant in nature we have the odorous esters, as well as carboxylic acids and phenols.
Inorganic chemical functions
Although many sources speak of four inorganic chemical functions: oxides, acids, bases and salts, in reality there are many more; but these are generally the most important. Not only oxides define a chemical function, but also sulphides and hydrides, as well as phosphides, nitrides, carbides, silicides, etc.
However, such compounds can be classified as ionic, falling within the function corresponding to salts. Likewise, a select group of compounds with advanced properties are less abundant and considered more than families. Therefore, only the four functions mentioned above will be addressed.
- Oxides
By chemical function, oxides are understood to be all those inorganic compounds that contain oxygen. There being metals and non-metals, separately they will form different oxides, which in turn will give rise to other compounds. This function also includes peroxides (O 2 2-) and superoxides (O 2 -), although they will not be discussed.
Metallic or basic oxides
When metals react with oxygen, oxides are formed whose general formula is M 2 O n, where n is the oxidation number of the metal. We therefore have metal oxides, which are basic because when they react with water, they release OH - ions, from the hydroxides generated, M (OH) n.
For example, magnesium oxide is Mg 2 O 2, but the subscripts can be simplified to make the formula MgO. As MgO dissolves in water, it produces magnesium hydroxide, Mg (OH) 2, which in turn releases OH ions - according to its solubility.
Acidic oxides or anhydrides
When a non-metallic element (C, N, S, P, etc.) reacts with oxygen, an acid oxide is formed, since when dissolved in water it releases H 3 O + ions from the oxacids produced. Acidic oxides are the "dry version" of oxacids, which is why they are also called anhydrides:
Non-metal + O 2 => Acidic oxide or anhydride + H 2 O => Oxacid
For example, carbon reacts completely with oxygen to generate carbon dioxide, CO 2. When this gas dissolves in water at high pressure, it reacts to transform into carbonic acid, H 2 CO 3.
Neutral oxides
Neutral oxides do not dissolve in water, so they do not generate OH - ions or H 3 O +. Examples of these oxides are: CO, MnO 2, NO, NO 2 and ClO 2.
Mixed oxides
Mixed oxides are those formed by more than one metal, or the same metal with more than one oxidation number. For example, magnetite, Fe 3 O 4, is really an FeO · Fe 2 O 3 mixture.
- You go out
Salts are ionic compounds, so they contain ions. If the ions come from two different elements, we will have binary salts (NaCl, FeCl 3, LiI, ZnF 2, etc.). While, if two elements also contain oxygen, they will be treated ternary or oxisales salts (NaNO 3, MnSO 3, CuSO 4, CaCrO 4, etc.).
- Acids
Mention was made of oxacids, whose general formula is H a E b O c. For the case of carbonic acid, H 2 CO 3, a = 2, b = 1 and c = 3. Another important group of inorganic acids are the hydracids, which are binary and do not have oxygen. For example: H 2 S, hydrogen sulfide, as dissolved in water produces H 3 O + ions.
- Bases
The bases come to be those compounds that release OH - ions, or at least as far as inorganic is concerned.
Organic chemical functions
Organic chemical functions are more appropriately named functional groups. It is no longer a question of having ions or a specific atom, but rather a set of atoms that provide the molecule with some qualities regarding its reactivity. Each functional group can house hundreds of thousands of organic compounds.
Of course, more than one functional group can be present in a molecule, but the most reactive group predominates in its classification; which is usually the most rusty. Thus, some of these groups or functions are listed:
-Alcohols, -OH
-Carboxylic acids, -COOH
-Amines, -NH 2
-Aldehydes, -COH or -CHO
-Amides, -COONH 2
-Tiols, -SH
-Esters, -COO-
-Ethers, -OR-
Examples of chemical functions
In the previous sections several examples of compounds belonging to a specific chemical function have been cited. Here others will be mentioned followed by their chemical function, be it inorganic or organic:
-FeTiO 3, mixed oxide
-Pb 3 O 4, mixed oxide
-HNO 3, oxacid
-Ca (NO 3) 2, oxisal
-BaO, basic oxide
-NaOH, base
-NH 3, base, since it releases OH ions - when dissolved in water
-CH 3 OH, alcohol
-CH 3 OCH 3, ether
-HF, acidic acid
-HI, acidic acid
-CH 3 CH 2 NH 2, amine
-CH 3 COOH, carboxylic acid
-NaBr, binary salt
-AgCl, binary salt
-KOH, base
-MgCrO 4, ternary salt, although the central element is a metal, chromium, derived from chromic acid, H 2 CrO 4
-NH 4 Cl, binary salt, -CH 3 CH 2 CH 2 COOCH 3, ester
-SrO, basic oxide
-SO 3, acid oxide or anhydride
-SO 2, acid oxide or anhydride
-NH 4 Cl, binary salt, because the NH 4 + cation counts as an individual ion even though it is polyatomic
-CH 3 SH, thiol
-Ca 3 (PO 4) 2, ternary salt
-NaClO 3, ternary salt
-H 2 Se, acidic acid
-H 2 Te, acid hydrazide
-Ca (CN) 2, binary salt, since the CN anion - is again considered as a single ion
-KCaPO 4, mixed salt
-Ag 3 SO 4 NO 3, mixed salt
References
- Whitten, Davis, Peck & Stanley. Chemistry (8th ed.). CENGAGE Learning.
- Graham Solomons TW, Craig B. Fryhle. (2011). Organic Chemistry. Amines. (10th edition.). Wiley Plus.
- Wikipedia. (2019). Chemical functions. Recovered from: es.wikipedia.org
- The Editors of Encyclopaedia Britannica. (2015, August 24). Inorganic compound. Encyclopædia Britannica. Recovered from: britannica.com
- Khan Academy. (2019). Inorganic chemical functions. Recovered from: es.khanacademy.org
- Carlos Eduardo Núñez. (2012). Chemical functions of organic compounds.. Recovered from: cenunez.com.ar