Substance group

The substance group of noble gases , here glowing in its own light: All noble gases, for example, are colorless and odorless, extremely inert and therefore non-flammable

Substances from the group of alkali metals : All alkali metals are extremely sensitive to air and water. They are flammable, react with water to form alkalis and hydrogen gas, with non-metals and acids to form salts and they color the flame

In chemistry, a group or class of substances is understood to mean all substances that can be grouped together by a common property. Each substance can belong to several groups, depending on which property is used for classification . There is no fixed number of possible groups, rather a new substance group can be defined depending on the occasion and the connecting properties.

Subdivision

Basically, there are the chemical elements of the chemical compounds , which are composed of two or more elements. Elements can in turn be subdivided according to their metallic properties or their position in the periodic table , compounds according to their type of bond and the number of elements involved.

Further subgroups can be divided into:

Groups of substances that are formed according to their chemical composition and chemical-functional properties (example: oxides as compounds of oxygen, acids as corrosive hydrogen compounds).
Groups of substances, according to the respective applications (uses), and the corresponding material properties are formed (for example, fertilizers , explosives and nutrients as for metabolism and digestion usable pure substances and mixtures of substances , combat and toxins as a means for killing of certain living beings, even pesticides or pesticide called ).
In medicine, according to their effects in or on organisms (for example hormones, vitamins and fragrances and flavorings).
Substance groups that are differentiated according to the good or bad solubility of compounds in water.
Substance groups that can be differentiated according to their occurrence and origin (e.g. raw materials , natural substances and plastics ).

1941 Gerold Schwarzenbach leads in the book general and inorganic chemistry. A simple textbook on a modern basis with a division into "predominantly non-polar and volatile substances", "salt-like substances", "diamond-like and graphite-like substances" and "metallic substances", which is outdated in chemistry today, but still in some chemistry textbooks can be found. "Diamond-like substances" are characterized by very high hardness, high melting and boiling points and completely insoluble in water. They typically have an atomic bond. A similar classification was discussed as early as 1928. Later textbooks added the group of "plastics or high molecular substances".

Chemical elements

The elements can be classified according to

Metallic properties. A distinction is made between metals , semi-metals and non-metals .
State at room temperature : solids, liquids ( bromine and mercury only ) and gases
Position in the periodic table of the elements
- Main group and sub group elements.

Main group	Subgroup
Main group I: alkali metals Main group II: alkaline earth metals Main group III: boron group , "earth metals" Main group IV: carbon group Main group V: nitrogen group Main group VI: chalcogens , (oxygen group) Main group VII: halogens Main group VIII: noble gases	Group 03: scandium group Group 04: titanium group Group 05: vanadium group Group 06: chromium group Group 07: Manganese group Group 08: iron group Group 09: cobalt group Group 10: nickel group Group 11: copper group Group 12: zinc group
Remarks ↑ For main group elements only the s and p orbitals are newly occupied compared to their predecessors ↑ For subgroup atoms the d orbital and for the lanthanides and actinides also the f orbital.

Compound classes

Classification by type of tie
- Molecular compounds
- Salts (ionic bond). The salts are mostly divided according to their anions . Examples are
  - Chlorides , fluorides , iodides , bromides , chlorates , bromates , iodates (halides and halogen-oxygen compounds)
  - Sulfates , sulfides , sulfites (sulfur and sulfur-oxygen anions)
  - Nitrates , nitrites , amides (nitrogen compounds)
- Organometallic compounds ( atomic bond )
- Complexes (complex binding, association)
Classification according to the number of elements involved: binary, ternary and quaternary connections (two to four elements)
Organic and inorganic compounds

Organic compounds

The most extensive group of substances in chemistry in terms of the number of substances is the substance group of carbon compounds (over 7 million substances). It includes all substances with a basic structure made up of carbon atoms. In organic chemistry, the functional group of a compound is decisive for this classification. For example, compounds that have a hydroxyl group in their carbon chain belong to the alcohol class .

In a further definition, a substance class (such as alcohols) can also contain further functional groups. In addition, in a broader definition, there are also substance classes that are characterized by the fact that they contain a certain combination of several functional groups, for example the amino acids.

Examples of organic substance classes: hydrocarbons ,

Alkanes , alkenes , alkynes , alkanols (alcohols) , alkanoic acids , alicyclics , amides , amines , amino acids , aromatics , alkanones (ketones) , alkanals (aldehydes) ,
Carboxylic acids and carboxylic acid derivatives such as carboxylic acid chlorides , carboxylic acid anhydrides ,
Epoxides , esters , ethers
Furans
Haloalkanes , hydrazines, heterocycles
Imine
Oxiranes
Thiols , thioethers

Substance groups according to structure and composition

Other chemical groups, subdivided according to chemical-functional properties and structure, are for example:

In the case of the elements, the noble gases such as helium , neon etc., the alkali metals , the non-ferrous metals etc.
in the case of salts, the chlorides , oxides , sulphides , sulphates , lead, iron, ammonium , copper and sodium salts etc.
In the case of molecular compounds, the acids , alkenes , non-metal oxides, hydrides , CFCs , etc.
For metals, according to chemical stability in the environment: precious metals and base metals

acids and bases

Both organic and inorganic substances can form acids and bases . The decisive factor is the ability to be able to release (acids) or absorb (base) protons , usually in aqueous solution . Organic acids are, for example, carboxylic acids , inorganic acids include nitric acid , sulfuric acid and hydrogen chloride . Organic bases are almost all amines , inorganic bases are all hydroxide salts of alkali and alkaline earth metals (such as sodium hydroxide ).

Substance groups according to application and properties

Water - the most important of all solvents

Substance groups can also be classified according to their use and effect and also include substance mixtures . These include, for example:

Dyes , colorants / pigments and bleaches to decolorize them
Fertilizers , nutrients and roughage , bitter, sweetener, spices and flavorings
Adhesives , thickeners and binders, as well as thinners, solvents and pickling agents for removing bound substances
Explosives
Medicines and remedies ( active ingredients )
Pest control agents ( pesticides ), ordnance ( chemical weapons ) and toxins
Addictive substances ( drugs ) and antidotes (antidotes, antidotes )

In chemistry , groups of substances are also formed according to their intended use in the chemistry laboratory :

Detection means are reagents for detection reactions ( e.g. cation detection )

Precipitants are reagents for converting soluble into insoluble compounds (e.g. for separation, see cation separation process )

Reducing agents and oxidizing agents are reagents used in redox reactions

Disintegration agents are used in digestion processes to convert insoluble into soluble and thus detectable compounds

Natural substances

The dye indigo , of course

Natural macromolecular substances (such as lignin , cellulose and starch )
Hydrocarbons such as petroleum and natural gas
Nature-identical fabrics
Dyes

More fabrics

Plastics are classified on the one hand according to the type of polymerization and on the other hand according to the type of monomers . Examples are polyester , polyvinyl chloride and polystyrene . A distinction is also made as to whether a plastic consists of one type of monomer or of several, the latter being referred to as copolymer .
In biochemistry, a distinction is made between the four substance classes proteins , carbohydrates , lipids and nucleic acids , which are considered to be the building blocks of living organisms.
Drugs are (bio) chemical substances that affect a person's consciousness and, in a more general sense, physiologically active substances. The two most important classes of substances are alkaloids and terpenoids with various subclasses.
Chemical warfare agents are poisons that are used against people. A classification is made according to the affected biochemical system and the effect.

Web links

Substance groups on Umweltbundesamt.de
Substance classes and functional groups. (PDF) at oecho.at

Individual evidence

↑ Federal Environment Agency: groups of substances | Federal Environment Agency , accessed on June 5, 2020
↑ ^a ^b Dieter Holzner, Karsten Holzner: Chemistry for technical assistants in medicine and in biology . John Wiley & Sons, 2018, ISBN 978-3-527-34283-9 , pp. 18 ( limited preview in Google Book search).
↑ CHRISTEN: Chemistry Lessons A practice-oriented didactics . Springer-Verlag, 2013, ISBN 978-3-0348-5218-0 , pp. 94 ( limited preview in Google Book search).
^ Chemistry today SI . Schroedel, 2013, ISBN 978-3-507-88053-5 .
^ Hans Rudolf Christen: Chemistry . Sauerländer, 1974, p. 20 ( limited preview in Google Book search).
↑ The types of chemical bonds and the structure of atoms: 42 lectures (with ... - German Bunsen Society for Physical Chemistry) . Verlag Chemie, 1928, p. 11 ( limited preview in Google Book search).
↑ Ralf Geiß: The transformation of fabrics . Springer-Verlag, 2017, ISBN 978-3-662-54708-3 , pp. 335 ( limited preview in Google Book search).
↑ Olaf Kühl: Organic Chemistry. For biochemists, life scientists, physicians, pharmacists . Wiley-VCH, Weinheim 2012, ISBN 978-3-527-33199-4 , pp. 239 .

[8] For main group elements only the s and p orbitals are newly occupied compared to their predecessors

[9] For subgroup atoms the d orbital and for the lanthanides and actinides also the f orbital.

[umweltbundesamt.de-1] Federal Environment Agency: groups of substances | Federal Environment Agency , accessed on June 5, 2020

[Dieter_Holzner,_Karsten_Holzner-2] Dieter Holzner, Karsten Holzner: Chemistry for technical assistants in medicine and in biology . John Wiley & Sons, 2018, ISBN 978-3-527-34283-9 , pp. 18 ( limited preview in Google Book search).

[CHRISTEN-3] CHRISTEN: Chemistry Lessons A practice-oriented didactics . Springer-Verlag, 2013, ISBN 978-3-0348-5218-0 , pp. 94 ( limited preview in Google Book search).

[4] Chemistry today SI . Schroedel, 2013, ISBN 978-3-507-88053-5 .

[Hans_Rudolf_Christen-5] Hans Rudolf Christen: Chemistry . Sauerländer, 1974, p. 20 ( limited preview in Google Book search).

[6] The types of chemical bonds and the structure of atoms: 42 lectures (with ... - German Bunsen Society for Physical Chemistry) . Verlag Chemie, 1928, p. 11 ( limited preview in Google Book search).

[Ralf_Geiß-7] Ralf Geiß: The transformation of fabrics . Springer-Verlag, 2017, ISBN 978-3-662-54708-3 , pp. 335 ( limited preview in Google Book search).

[10] Olaf Kühl: Organic Chemistry. For biochemists, life scientists, physicians, pharmacists . Wiley-VCH, Weinheim 2012, ISBN 978-3-527-33199-4 , pp. 239 .