WHAT ARE INORGANIC CHEMICAL FUNCTIONS? - CHEMISTRY - 2024

The inorganic chemical functions are those families of inorganic compounds that share similar chemical characteristics. These chemical functions are made up of five groups: oxides, bases or hydroxides, acids, salts, and hydrides.

Each chemical function is defined by a set of atoms that identify them. In this way, it becomes possible to identify the function to which a chemical compound belongs according to its elements.

In this sense, we can state that the OH group defines the chemical function of the hydroxide. Therefore, NaOH (sodium hydroxide) will belong to the group of hydroxides.

Inorganic chemical functions take advantage of the use of chemical compounds of mineral origin. Salt, water, gold, lead, gypsum and talc are some examples of inorganic compounds in daily use.

All inorganic compounds have existed on planet earth before life originated. With atomic theory, the development of the periodic table and radiochemistry, it was possible to define the five functions of inorganic chemistry.

The first investigations and approaches on the subject took place at the beginning of the 19th century and were based on the study of simple inorganic compounds (salts and gases).

Inorganic chemical functions

- Oxides

Red lead, a crystalline compound containing lead oxide. Source: BXXXD, via Wikimedia Commons

Oxides are double or binary compounds where one or more oxygen atoms are combined with other elements. For this reason, there are many types of oxides in different states of matter (solid, liquid and gaseous).

Oxygen always contributes an oxidation state of -2, and almost all the elements that combine with it give rise to stable compounds in different degrees of oxidation.

Thanks to these, the compounds obtained have varied properties and can have both covalent and solid ionic bonds.

Basic oxides

Basic oxides are compounds derived from the mixture of oxygen with a metal (transition, alkaline earth or alkaline). For example, the combination of magnesium with oxygen results in a basic oxide, like this:

2Mg + O2 → 2 MgO

Metal + oxygen = basic oxide

2MgO = Basic oxide

Nomenclature

The nomenclature of the oxides is always the same. First the generic name of the compound (oxide) is indicated, and later the name of the metal is written. This happens as long as the valence of the metal is fixed.

An example can be sodium oxide or Na2O, where the symbol for metal goes first and then that of oxygen with its valence or oxidation state of -2.

In the case of basic oxides there are three types of nomenclature: the traditional, the atomic and the Stock numeral. The name of each basic oxide will depend on the valence or oxidation number of each element.

characteristics

- They are always formed by combining any element with oxygen.

- Binary oxides are those that are obtained by mixing oxygen with another element.

- To obtain a ternary or mixed oxide, a binary compound must be combined with water (H2O).

- There are mixed oxides resulting from the combination of two different elements with oxygen.

- Bases or hydroxides

Bases

Their taste is bitter, their texture is soapy to the touch, they are good conductors of electrical current when in an aqueous solution, they are corrosive and when they touch litmus paper they turn it from pink to blue.

characteristics

- They are derived from the mixture of a basic oxide with water.

- The substances they create can receive protons.

- They are conductors of electricity called electrolytes.

- They are soluble in water when they come into contact with it.

- Its taste is bitter.

- They are corrosive to the skin.

- Acids

Acetic acid, a weak acid, donates a proton (hydrogen ion, highlighted in green) to water in an equilibrium reaction to give the acetate ion and the hydronium ion. Red: oxygen. Black: carbon. White: hydrogen.

Acids are inorganic compounds that result from mixing hydrogen with any element or group of elements with high electronegativity.

They can be easily identified by their acidic taste, because they can burn the skin when they come in direct contact with it, and because of their ability to change the color of litmus paper from blue to pink.

Hydracids

Hydracids are a group of acids derived from the combination of hydrogen with a non-metal. An example can be the combination of chlorine with hydrogen that results in hydrochloric acid, like this:

Cl2 + H2 → 2HCL

Nonmetal + Hydrogen = Hydracid

H2CL = Hydracid

Oxacids

Oxacids are a group of acids derived from the combination of water with an acid oxide. An example can be the combination of sulfur trioxide with water that results in sulfuric acid, like this:

SO3 + H2O → H2SO4

Acidic oxide + water = Oxacid

H2SO4 = Oxacid

characteristics

- They burn the skin as they are corrosive.

- Its flavor is sour.

- They are conductors of electrical current.

- When reacting with a base they form a salt and water.

- When reacting with a metallic oxide they form a salt and water.

- You go out

Salts are compounds that are derived from combining a base with an acid. They generally have a salty taste and are in an acid state.

They are good electrical conductors in aqueous solutions. In contact with litmus paper they do not affect its color.

Haloids

Haloid salts are those that lack oxygen and are formed through the following reactions:

1 - When mixed with a halogen metal. An example can be the combination of magnesium with hydrochloric acid to form magnesium chloride and hydrogen, like this:

Mg + 2HCl → MgCl2 + H2

2 - When mixing an active metal with a hydracid. An example can be the combination of hydrobromic acid with sodium oxide, which results in sodium bromide and water, like this:

2HBr + 2NaO 2 → NaBr + H2O

3 - When mixing a hydracid with a metallic oxide. An example can be the combination of hydrochloric acid with sodium hydroxide to form sodium chloride and water, like this:

HCl + NaOH → NaCl + H2O

- Oxisales

Sodium bicarbonate, oxisal

Oxysalts are those salts that contain oxygen. They are formed as follows:

1 - When mixing a hydracid with a hydroxide. This is a neutralization process. An example can be the mixture of magnesium with sulfuric acid to form magnesium sulfate and water, like this:

Mg + H2SO4 → MgSO4 + H2O

2 - When mixing an oxacid with an active metal. An example could be the combination of calcium hydroxide with carbon dioxide to give calcium carbonate and water, like this:

Ca (OH) 2 + CO2 → CaCO3 + H2O

3 - When mixing a hydroxide with an anhydride.

4 - When mixing a hydroxide with an oxacid. An example might be the combination of nitric acid with barium hydroxide to give barium nitrate and water, like this:

2HNO3 + Ba (OH) 2 → Ba (NO3) 2 + 2H2O

characteristics

- They have a salty taste.

- They can be acidic or basic.

- They are good electrical conductors.

- Hydrides

Aluminum lithiumhydride

Hydrides are inorganic chemical compounds made up of hydrogen and any non-metallic element.

They are usually in the gaseous state and have properties similar to those of acids. However, there are certain special hydrides such as water (H2O) that can be in a liquid state at room temperature.

Nomenclature

To formulate a hydride, first write the symbol for hydrogen and then that for the element.

To name them, the suffix uro and the nonmetal root are added, specifying the presence of hydrogen. Some examples are the following:

HF = Hydrogen Fluoride

HCl = Hydrogen Chloride

HBr = Hydrogen bromide

References

1. (November 21, 2011). BuenasTareas.com. Obtained from Oxides, acids, hydroxides, haloid salts etc: goodtasks.com.
2. García, RE (2007). Inorganic Chemical Functions and It's Nomenclature / Inorganic Chemical Functions and It's Nomenclature. Editorial Trillas.
3. House, JE, & House, KA (2016). Descriptive Inorganic Chemistry. London: Elsevier.
4. Vasquez, LN, & Blanco, WY (April 25, 2013). Chemistry Obtained from Oxides, Hydroxides, Acids and Salts: quimicanataliamywendyd.blogspot.com.
5. Williams, A. (1979). A Theoretical Approach to Inorganic Chemistry. Berlin: Springer - Verlag.