Clever Geek Handbook

Phosphorus and its compounds. Practical use of phosphorus compounds

Among the nutrients, phosphorus is a particular place. Indeed, without it, the existence of such vital compounds as, for example, ATP or phospholipids, as well as many other organic substances, is impossible . Moreover, the inorganics of this element are very rich in various molecules. Phosphorus and its compounds are widely used in industry, are important participants in biological processes, and are used in a variety of fields of human activity. Therefore, we consider what this element is, what is its simple substance and the most important compounds.

phosphorus and its compounds

Phosphorus: general characteristic of an element

The situation in the periodic system can be described in several paragraphs.

  1. Fifth group, main subgroup.
  2. The third minor period.
  3. The serial number is 15.
  4. The atomic mass is 30.974.
  5. The electronic configuration of the atom is 1s 2 2s 2 2p 6 3s 2 3p 3 .
  6. Possible oxidation states are from -3 to +5.
  7. The chemical symbol is P, pronunciation in pe formulas. The name of the element is phosphorus. The Latin name is Phosphorus.

The history of the discovery of this atom has its roots in the distant XII century. Even in the records of alchemists, there was information indicating the receipt of an unknown "luminous" substance. However, the official date for the synthesis and discovery of phosphorus was 1669. The bankrupt merchant merchant Brand, in search of a philosopher's stone, accidentally synthesized a substance capable of emitting a glow and burning with a bright blinding flame. He did this by repeatedly calcining human urine.

After it, independently of each other, in approximately the same ways, this element was received:

  • I. Kunkel;
  • R. Boyle;
  • A. Marggrave;
  • K. Scheele;
  • A. Lavoisier.

Today, one of the most popular methods for the synthesis of this substance is reduction from the corresponding phosphorus-containing minerals at high temperatures under the influence of carbon monoxide and silica. The process is carried out in special furnaces. Phosphorus and its compounds are very important substances for living beings, as well as for many syntheses in the chemical industry. Therefore, we should consider what constitutes this element as a simple substance and where in nature it is contained.

oxygen-containing organic compounds

Simple substance phosphorus

It is difficult to name any particular compound when it comes to phosphorus. This is due to the many allotropic modifications that this element has. There are four main varieties of the simple substance of phosphorus.

  1. White. This is a compound whose formula is P 4 . It is a white volatile substance with a sharp unpleasant odor of garlic. It ignites spontaneously in air at ordinary temperature. Burns with a luminous pale green light. Very poisonous and life threatening. The chemical activity is extremely high, so get it and store it under a layer of purified water. This is possible due to poor solubility in polar solvents. Carbon disulphide and organic matter are best suited for white phosphorus. When heated, it is able to transfer to the following allotropic form - red phosphorus. During condensation and cooling of vapors, it is able to form layers. To the touch greasy, soft, easily cut with a knife, white (slightly yellowish). Melting point 44 0 . Due to its chemical activity it is used in syntheses. But due to the toxicity it does not have wide industrial applications.
  2. Yellow. This is a poorly purified form of white phosphorus. It is even more poisonous, it also smells bad of garlic. It ignites and burns with a bright luminous green flame. These yellow or brown crystals do not dissolve in water at all, with complete oxidation they emit puffs of white smoke with a composition of P 4 O 10 .
  3. Red phosphorus and its compounds are the most common and most commonly used in industry modification of this substance. The pasty red mass, which at elevated pressure can transform into the form of violet crystals, is chemically inactive. This is a polymer that can dissolve only in certain metals and nothing else. At a temperature of 250 0 C sublimates, turning into a white modification. Not as toxic as previous forms. However, with prolonged exposure to the body is toxic. It is used in the application of igniter coatings on matchboxes. This is due to the fact that it cannot ignite spontaneously, but during denotation and friction it explodes (ignites).
  4. The black. According to external data, it is very similar to graphite, it is also greasy to the touch. This is a semiconductor of electric current. Dark crystals, brilliant, which are not able to dissolve in any solvents at all. In order for it to catch fire, very high temperatures and preliminary heating are needed.

Also of interest is the recently discovered form of phosphorus - metallic. It is a conductor and has a cubic crystal lattice.

the use of phosphorus and its compounds

Chemical properties

The chemical properties of phosphorus depend on what form it is in. As mentioned above, the most active yellow and white modification. In general, phosphorus is able to interact with:

  • metals, forming phosphides and acting as an oxidizing agent;
  • non-metals, acting as a reducing agent and forming volatile and non-volatile compounds of various kinds;
  • strong oxidizing agents, turning into phosphoric acid;
  • with concentrated caustic alkali according to the type of disproportionation;
  • with water at a very high temperature;
  • with oxygen to form various oxides.

The chemical properties of phosphorus are similar to those of nitrogen. After all, he is part of the group of pathogens. However, activity is several orders of magnitude higher due to the diversity of allotropic modifications.

Being in nature

As a nutrient, phosphorus is very common. Its percentage in the earth's crust is 0.09%. This is a fairly large indicator. Where does this atom occur in nature? There are several main places:

  • the green part of plants, their seeds and fruits;
  • animal tissues (muscles, bones, tooth enamel, many important organic compounds);
  • Earth's crust;
  • the soil;
  • rocks and minerals;
  • sea ​​water.

In this case, we can only talk about related forms, but not about simple matter. After all, he is extremely active, and this does not allow him to be free. Among the minerals, the richest in phosphorus are:

  • English;
  • fluorapaptite;
  • swanbergite;
  • phosphorite and others.

The biological significance of this element cannot be overestimated. After all, it is part of such compounds as:

  • proteins;
  • phospholipids;
  • DNA
  • RNA
  • phosphoproteins;
  • enzymes.

That is, all those that are vital and from which the whole organism is built. The daily norm for an ordinary adult is about 2 grams.

chemical properties of phosphorus

Phosphorus and its compounds

As very active, this element forms many different substances. After all, it forms phosphides, and itself acts as a reducing agent. Due to this, it is difficult to name an element that would be inert when reacting with it. And therefore, the formulas of phosphorus compounds are extremely diverse. There are several classes of substances in the formation of which he is an active participant.

  1. Binary compounds - oxides, phosphides, volatile hydrogen compounds, sulfide, nitride and others. For example: P 2 O 5 , PCL 3 , P 2 S 3 , PH 3 and others.
  2. Complex substances: salts of all types (medium, acidic, basic, double, complex), acids. Example: H 3 PO 4 , Na 3 PO 4 , H 4 P 2 O 6 , Ca (H 2 PO 4 ) 2 , (NH 4 ) 2 HPO 4 and others.
  3. Oxygen-containing organic compounds: proteins, phospholipids, ATP, DNA, RNA and others.

Most of the indicated types of substances have important industrial and biological significance. The use of phosphorus and its compounds is possible for medical purposes, and for the manufacture of quite ordinary household items.

Metal compounds

Binary compounds of phosphorus with metals and less electronegative non-metals are called phosphides. These are salt-like substances that have extreme instability when exposed to different agents. Rapid decomposition (hydrolysis) causes even ordinary water.

In addition, under the action of non-concentrated acids, the substance also decomposes into the corresponding products. For example, if we talk about the hydrolysis of calcium phosphide, the products will be metal hydroxide and phosphine:

Ca 3 P 2 + 6H 2 O = 3Ca (OH) 2 + 2PH 3 ↑

And subjecting phosphide to decomposition under the action of mineral acid, we get the corresponding salt and phosphine:

Ca 3 P 2 + 6HCL = 3CaCL 2 + 2PH 3 ↑

In general, the value of the compounds under consideration is precisely in the fact that a hydrogen phosphorus compound is formed as a result, the properties of which we will consider below.

hydrogen phosphorus compound

Phosphorus Volatile Substances

There are two main ones:

  • white phosphorus;
  • phosphine.

We already mentioned the first above and the characteristics were given. They said that it was thick white smoke, highly toxic, unpleasantly smelling and self-igniting under ordinary conditions.

But what is phosphine? This is the most common and well-known volatile substance, which includes the element in question. It is binary, and the second participant is hydrogen. The formula of the hydrogen phosphorus compound is PH 3 , the name is phosphine.

The properties of this substance can be described as follows.

  1. Colorless volatile gas.
  2. Very poisonous.
  3. It has the smell of rotten fish.
  4. It does not interact with water and dissolves very poorly in it. It is soluble in organics.
  5. Under normal conditions, very reactive.
  6. Self-igniting in air.
  7. It is formed during the decomposition of metal phosphides.

Another name is phosphane. Associated with stories from antiquity. It's all about the "wandering lights" that people sometimes saw and see now in cemeteries, swamps. The spherical or candle-like lights that arise here and there, giving the impression of movement, were considered a bad omen and superstitious people were very afraid of them. The cause of this phenomenon, according to the modern views of some scientists, can be considered spontaneous combustion of phosphine, which is formed naturally by the decomposition of organic residues, both plant and animal. Gas escapes and, in contact with oxygen, ignites. The color and size of the flame may vary. Most often, these are greenish bright lights.

Obviously, all volatile phosphorus compounds are toxic substances that are easily detected by a pungent unpleasant odor. This symptom helps to avoid poisoning and unpleasant consequences.

formulas of phosphorus compounds

Non-metal compounds

If phosphorus behaves as a reducing agent, then we should talk about binary compounds with non-metals. Most often, they are more electronegative. So, we can distinguish several types of substances of this kind:

  • a compound of phosphorus and sulfur - phosphorus sulfide P 2 S 3 ;
  • phosphorus chloride III, V;
  • oxides and anhydride;
  • bromide and iodide and others.

The chemistry of phosphorus and its compounds is diverse, so it is difficult to identify the most important of them. Speaking specifically about the substances that are formed by their phosphorus and non-metals, the most important are oxides and chlorides of different compositions. They are used in chemical synthesis as dewatering agents, as catalysts, and so on.

So, one of the most powerful drying agents is the highest phosphorus oxide - P 2 O 5 . It attracts water so much that in direct contact with it there is a violent reaction with strong noise. The substance itself is a white snowy mass, in the state of aggregation closer to amorphous.

Oxygen-containing organic compounds with phosphorus

It is known that organic chemistry is much larger than inorganic in the number of compounds. This is due to the phenomenon of isomerism and the ability of carbon atoms to form various structures of a chain of atoms, closing with each other. Naturally, there is a certain order, that is, a classification to which all organic chemistry obeys. The classes of compounds are different, however, we are interested in one specific, directly related to the element in question. These are oxygen-containing compounds with phosphorus. These include:

  • coenzymes - NADP, ATP, FMN, pyridoxalphosphate and others;
  • proteins;
  • nucleic acids, since the remainder of phosphoric acid is part of the nucleotide;
  • phospholipids and phosphoproteins;
  • enzymes and catalysts.

The type of ion in which phosphorus is involved in the formation of a molecule of these compounds is as follows: PO 4 3- , that is, it is an acid residue of phosphoric acid. It is part of some proteins as a free atom or a simple ion.

For the normal functioning of every living organism, this element and the organic compounds formed by it are extremely important and necessary. Indeed, without protein molecules, it is impossible to build a single structural part of the body. And DNA and RNA are the main carriers and transmitters of hereditary information. In general, all compounds must be present without fail.

chemistry of phosphorus and its compounds

The use of phosphorus in industry

The use of phosphorus and its compounds in industry can be characterized in several points.

  1. They are used in the production of matches, explosive compounds, incendiary bombs, certain types of fuel, and lubricants.
  2. As an absorber of gases, as well as in the manufacture of incandescent lamps.
  3. To protect metals from corrosion.
  4. In agriculture as soil fertilizer.
  5. As a means to soften water.
  6. In chemical synthesis in the production of various substances.

The role in living organisms is reduced to participation in the processes of formation of tooth enamel and bones. Participation in the reactions of ana- and catabolism, as well as maintaining the buffering of the internal environment of the cell and biological fluids. It is the basis in the synthesis of DNA, RNA, phospholipids.

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