What is a Chemical Compound?

What Does Chemical Compound Mean

A chemical compound is any substance formed by the union of two or more types of chemical elements , that is, by atoms of two or more different types of chemical elements , linked together by chemical bonds of some kind.



A chemical compound cannot be separated into its constituent elements by physical methods ( distillation , decantation , etc.). The only way to separate a chemical compound into its constituent elements is through chemical reactions .

The level of complexity of a chemical compound can be very simple or very complex, this depends on the number of atoms that form it and the way in which they combine. There are compounds made up of a few atoms and compounds made up of hundreds of atoms linked and occupying very specific positions in the compound.

For example, binary substances such as carbon dioxide (CO 2 ) or water (H 2 O) are chemical compounds . So are other more complex ones like sulfuric acid (H 2 SO 4 ) or glucose (C 6 H 12 O 6 ), or even inexpressible macromolecules in a simple chemical formula, like a human DNA molecule .

Despite being more or less complex agglomerations of elements, chemical compounds present a stable set of physical and chemical properties .

On the other hand, an apparently minor change in the configuration of its constituent atoms can produce radical changes in these properties , or it can produce entirely new substances through a chemical reaction.

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Types of chemical compounds

Chemical compounds can be classified according to two different criteria, which are:

  • According to the type of bond between its atoms. Depending on what type of bond exists between the constituent elements of a chemical compound, they can be classified into:

    • Molecules . Joined by covalent bonds (electron compartment).
    • Ions . Linked by electromagnetic links and endowed with a positive or negative charge.
    • Intermetallic compounds. Joined by metallic bonds , which usually occur obviously between metallic-type atoms.
    • Complex. That hold their long structures together through coordinated covalent bonds (it is a type of covalent bond in which the shared pair of electrons is contributed by only one of the atoms that participate in this bond).
  • According to the nature of its composition. Depending on the type of atoms that make them up, they can be classified into:

    • Organic compounds. They are those that have carbon as a base element, around which the other atoms are structured. They are the fundamental compounds for the chemistry of life . They may be:

      • Aliphatic. They are organic compounds that are not aromatic. They can be linear or cyclical.
      • Aromatics. They are organic compounds formed by structures with conjugated bonds. This means that a double or triple bond alternates with a single bond throughout the entire structure. They are very stable.
      • Heterocyclic. They are organic compounds whose structure is cyclical, but at least one atom of the cycle is an element other than carbon.
      • Organometallic. They are organic compounds in which a metal is also part of their structure.
      • Polymers . They are macromolecules made up of monomers (smaller molecules).
    • Inorganic compounds . They are those whose base is not always carbon. They are very diverse in nature and occur in all states of aggregation . These are classified into:

      • Basic oxides . They are formed when a metal reacts with oxygen. For example: iron (II) oxide (FeO)
      • Acidic oxides. They are formed by bonds between oxygen and a non-metallic element . For example: Chlorine (VII) oxide (Cl 2 O 7 )
      • Hydrocarbons. They can be metallic and non-metallic. Metal hydrides are formed by the union of a hydride anion (H - ) with a negative electrical charge, with any metal cation (positive charge). Non-metallic hydrides are formed by the union of a non-metal (which in this case always reacts with its lowest oxidation state) and hydrogen. The latter are generally gaseous and are named by prepending the name of the non-metal followed by the phrase -dehydrogen. For example: Lithium hydride (LiH), beryllium hydride (BeH 2 ), hydrogen fluoride (HF (g) ), hydrogen chloride (HCl (g) ).
      • Hydracids. They are compounds formed by hydrogen and a nonmetal. When dissolved in water they give acidic solutions. For example: hydrofluoric acid (HF (aq) ), hydrochloric acid (HCl (aq) ).
      • Hydroxides (or bases). They are compounds formed by the union of a basic oxide and water . They are recognized by the hydroxyl functional group -OH. For example: lead (II) hydroxide (Pb (OH) 2 ), lithium hydroxide (LiOH).
      • Oxacids. They are compounds that are also called oxoacids or oxyacids (and popularly "acids"). They are acids that contain oxygen. They are formed when an acid oxide and water react. For example: sulfuric acid (H 2 SO 4 ), hyposulfurous acid (H 2 SO 2 ).
      • You go out. Salts are the product of the union of acidic and basic substances. They are classified as: neutral, acidic, basic and mixed.

        • Neutral salts. They are formed by the reaction between an acid and a base or hydroxide, which releases water in the process. They can be binary and ternary depending on whether the acid is a hydracid or an oxacid respectively. For example: sodium chloride (NaCl), iron trichloride (FeCl 3 ), sodium phosphate (Na 3 PO 4 )
        • Acid salts. They are formed by the replacement of hydrogen in an acid by metal atoms. For example: sodium hydrogen sulfate (VI) (NaHSO4).
        • Basic salts. They are formed by replacing the hydroxyl groups of a base with the anions of an acid. For example: iron (III) dihydroxychloride (FeCl (OH) 2 ) .
        • Mixed salts. They are produced by replacing the hydrogens of an acid with metal atoms of different hydroxides. For example: sodium potassium tetraoxosulfate (NaKSO4).

Everyday Examples of Chemical Compounds

Much of the substances that surround us, such as milk, are compounds.

It is easy to find everyday examples of chemical compounds. Just take a look at the kitchen: the chemical compounds are water (H 2 O), sugar or sucrose (C 12 H 22 O 11 ), salt (NaCl), oil (glycerol and three carboxylate radicals) or vinegar , which is a dilution of acetic acid (C 2 H 4 O 2 ).

The same, although at much higher levels of complexity, occurs with butter, cheese, milk or wine .

Chemical elements and chemical compounds

Chemical elements are the different types of atoms that make up matter , and which are distinguished from each other according to the particular configuration of their subatomic particles ( protons , neutrons and electrons ).

Chemical elements can be grouped according to their chemical properties , that is, the forces to which they respond more or less easily, the behavior they exhibit in certain reactions, or other structural characteristics of their own. They are represented, classified and organized in the Periodic Table of the elements.

Chemical compounds are combinations of chemical elements of varying complexity. Chemical elements are the minimum pieces of matter, which cannot be decomposed into smaller pieces by physical methods (it is necessary to resort to chemical methods for this).

An example of a chemical compound is water. This compound is made up of hydrogen and oxygen. If the water molecule is decomposed, oxygen and pure hydrogen exist in their molecular forms in the gaseous state O 2 and H 2 .

Chemical composition of water

Water is a chemical compound of dipole molecules that attract each other.

As denoted by its chemical formula (H 2 O), despite being a simple substance, water is a chemical compound made up of two types of elements: hydrogen (H) and oxygen (O) , in a fixed proportion and determined in each of its molecules: two hydrogen atoms for each oxygen atom.

These atoms are linked by covalent bonds, which give the molecule great stability. In addition, they give it dipolar properties that allow the formation of bridges between the hydrogen atoms of a water molecule and the others (hydrogen bonds).

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