On what property of phosphorus oxide 5 is based. Oxygen compounds of phosphorus. Phosphorus in nature

Phosphorus is a vital element from the fifth group periodic table Mendeleeva. The chemical properties of phosphorus depend on its modification. The most active substance is a white phosphorus, oxidizing in air. Phosphorus has two valence (III and V) and three oxidation degrees - +5, +3, -3.

Phosphorus and compounds

Phosphorus has three allotropic modifications, characterized by chemical and physical properties:

• white;
• red;
• the black.

Under phosphorus in chemical reactions, white phosphorus (P 4) is most often understood. Red phosphorus reacts when certain conditions. For example, reacts with water when heating and under pressure. Black phosphorus is practically inert.

Fig. 1. Glowing white phosphorus.

Phosphorus reacts with simple and complex substancesBy forming:

• phosphine;
• phosphoric acid;
• phosphides;
• oxides.

Phosphine (pH 3) is poorly soluble in water poisonous gas, an analogue of ammonia. In the absence of oxygen, when heated is decomposed on simple substances - phosphorus and hydrogen.

Fig. 2. Phosphine.

Phosphoric or orthophosphoric acid (H 3 PO 4) is formed when phosphorus interacts or phosphorus oxide (V) with water.

Phosphides - salts formed when interacting with metals or non-metals. They are unstable and easily decomposed under the influence of acids or water.

Phosphorus can form two oxide - P 2 O 3 and P 2 O 5.

H 3 PO 4 - an acid of medium force, manifesting amphoteric properties when interacting with strong acid. Phosphoric acid forms phosphates.

Chemical properties

The main chemical properties of phosphorus and its connections are described in the table.

Substance	Reaction	Features	The equation
		With an excess of O 2, it forms phosphorus oxide (V)	4p + 5o 2 → 2P 2 O 5; 4p + 3O 2 → 2P 2 O 3
	With metal	Is an oxidizer	3mg + 2p → MG 3 P 2
	With halogens and non-metals	Does not react with hydrogen	2p + 3s → P 2 S 3
			8P + 12N 2 O → 5RN 3 + 3N 3 PO 2
	With acids		2p + 5h 2 SO 4 → 2H 3 PO 4 + 5SO 2 + 2H 2 O
	With alkalis		P 4 + 3NAOH + 3H 2 O → PH 3 + 3NAH 2 PO 2
		Flammable in air	PH 3 + 2O 2 → H 3 PO 4
	With halogens and non-metals		PH 3 + 2i 2 + 2H 2 O → H (pH 2 O 2) + 4hi
	With acids	Shows the properties of the reducing agent	PH 3 + 3H 2 SO 4 → H 2 (PHO 2) + 3SO 2 + 3H 2 O
	With metals	With active metals	2H 3 PO 4 + 3CA → CA 3 (PO 4) 2 + 3H 2
		Subject to dissociation	H 3 PO 4 + H 2 O ↔ H 3 O + + H2PO 4 -
	With alkalis	Forms acidic or alkaline phosphates	H 3 PO 4 + 3NAOH → Na 3 PO 4 + 3H 2 O
	With oxides		2H 3 PO 4 + 3K 2 O → 2K 3 PO 4 + 3H 2 O
			2H 3 PO 4 + 3Caco 3 → Ca 3 (PO 4) 2 + 3H 2 O + 3CO 2
	With ammonia		H 3 PO 4 + 3NH 3 → (NH 4) 3 PO 4
	With halogens and non-metals		2p 2 o 3 + 6Cl 2 → 4PCl 3 O + O 2; 2p 2 O 3 + 9S → P 4 S 6 + 3SO 2
		S. slowly reacts cold water And quickly - with hot	P 2 O 3 + 3H 2 O → 2H 3 PO 3
	With alkalis		P 2 O 3 + 4NAOH → 2NA 2 HPO 3 + H 2 O
		Reacts with an explosion	2p 2 O 5 + 6H 2 O → 4H 3 PO 4
	With acids	Recovery reaction	4HNO 3 + 2P 2 O 5 → 4HPO 3 + 2N 2 O 5
		Form hydroxides of metals and phosphine	Ca 3 P 2 + 6H 2 O → 3CA (OH) 2 + 2PH 3
	With acids	Recovery reaction	Ca 3 P 2 + 6HCl → 3CACL 2 + 2PH 3

When heated phosphorus oxide decays. Moreover, P 2 O 3 forms a red phosphorus, and P 2 O 5 - phosphorus (III) oxide and oxygen.

Fig. 3. Red phosphorus.

Using

Widespread use of phosphorus compounds:

• frequency and detergents are obtained from phosphates;
• phosphoric acid is used for fabric staining;
• phosphorus oxide (V) dries fluids and gases.

Red phosphorus is used in the production of matches and explosives.

What did we know?

Phosphorus is an active nonmetall reacting with simple and complex substances. As a result of the reactions, oxides (III) and (V), phosphine, phosphoric acid and phosphide are formed. Phosphorus compounds react with metals, non-metals, acids, alkalis, water. Phosphorus and its compounds are used in industry and agriculture.

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Phosphorus and its connections

Introduction

Chapter I. phosphorus as an element and as a simple substance

1.1. Phosphorus in nature

1.2. Physical properties

1.3. Chemical properties

1.4. Obtaining

1.5. Application

Chapter II. Phosphorus compounds

2.1. Oxides.

2.2. Acids and their salts

2.3. Phosphine

Chapter III. Phosphoric fertilizers

Conclusion

Bibliographic list

Introduction

Phosphorus (lat. Phosphorus) P - chemical element V groups of the periodic Mendeleev system atomic number 15, atomic weight 30,973762 (4). Consider the structure of the phosphorus atom. On the outer energy level Phosphorum atom are five electrons. Graphically it looks like this:

1s. 2 2s. 2 2p. 6 3s. 2 3p. 3 3d. 0

In 1699, the Hamburg Alchemist X. Brand in search of a "philosophical stone", allegedly able to turn non-denominated metals in gold, when evaporation of urine with coal and sand, allocated a white wax substance capable of glowing.

The name "phosphorus" comes from Greek. "Phos" - Light and "Phoros" - carrier. In Russia, the term "phosphorus" was introduced in 1746 M.V. Lomonosov.

The main compounds of phosphorus include oxides, acids and their salts (phosphates, dihydrophosphates, hydrophosphates, phosphides, phosphites).

Very many substances containing phosphorus are contained in fertilizers. Such fertilizers are called phosphate.

ChapterI. Phosphorus as an element and as a simple substance

1.1 Phosphorus in nature

Phosphorus refers to the number of common elements. Total content B. earth Kore It is about 0.08%. Due to light oxidizing, phosphorus is found only in the form of connections. The main minerals of phosphorus are phosphorites and apatites, from the latter the most common fluoropatite 3CA 3 (PO 4) 2 CAF 2 is most common. Phosphorites are widespread in the Urals, in the Volga region, Siberia, Kazakhstan, Estonia, Belarus. The biggest deposits of apatites are located on the Kola Peninsula.

Phosphorus is an essential element of living organisms. It is present in the bones, muscles, in brain fabric and nerves. ATP - adenosyntrifosphoric acid molecules (ATP - collector and energy carrier) were constructed from phosphorus. In the body of an adult, it contains an average of about 4.5 kg of phosphorus, mainly in conjunction with calcium.

Phosphorus is also contained in plants.

Natural phosphorus consists of only one stable isotope 31 R. Nowadays, six radioactive phosphorus isotopes are known.

1.2 Physical Properties

Phosphorus has several allotropic modifications - White, red, black, brown, purple phosphorus, etc. The first three of these are most studied.

White phosphorus - Colorless, with a yellowish tint, crystalline substance, luminous in the dark. Its density is 1.83 g / cm 3. It does not dissolve in water, it is well soluble in the servo carbon. It has a characteristic garlic smell. Melting point is 44 ° C, the temperature of self-ignition is 40 ° C. To protect the white phosphorus from oxidation, it is stored under water in the dark (there is a transformation into a red phosphorus). In the cold, white phosphorus fragile, at temperatures above 15 ° C becomes soft and cut into a knife.

White phosphorus molecules have a crystal grid, in the nodes of which are molecules P 4, having a tetrahedron form.

Each phosphorne atom is associated with three σ-bonds with other three atoms.

White phosphorus poisonous and gives it difficult to burn burns.

Red phosphorus- The powdered substance of the dark red color without smell, in water and the servo is not dissolved, does not shine. Flammation temperature 260 ° C, density 2.3 g / cm 3. The red phosphorus is a mixture of several allotropic modifications that differ in color (from scratch to violet). The properties of the red phosphorus depend on the conditions of its production. Not poisonous.

Black phosphorusby appearance Looks like graphite, greasy to the touch, has semiconductor properties. Density 2.7 g / cm 3.

Red and black phosphors have an atomic crystal lattice.

1.3 Chemical Properties

Phosphorus - Nemmetall. In the compounds, it usually shows the degree of oxidation +5, less often - +3 and -3 (only in phosphide).

Reactions with white phosphorus are lighter than with red.

I. Interaction S. simple substances.

1. Interaction with halogens:

2p + 3Cl 2 \u003d 2pCl 3 (phosphorus chloride (III)),

PCL 3 + Cl 2 \u003d PCl 5 (phosphorus chloride (V)).

2. Interaction with nonmatals:

2P + 3S \u003d P 2 S 3 (phosphorus sulfide (III).

3. Metal interaction:

2p + 3ca \u003d Ca 3 P 2 (calcium phosphide).

4. Interaction with oxygen:

4p + 5o 2 \u003d 2p 2 O 5 (phosphorus oxide (V), phosphoric anhydride).

II. Interaction with complex substances.

3p + 5hno 3 + 2H 2 O \u003d 3H 3 PO 4 + 5NO.

1.4 Receipt

Phosphorus is obtained from crushed phosphorites and apatites, the latter mixed with coal and sand and calcined in furnaces at 1500 ° C:

2CA 3 (PO 4) 2 + 10C + 6SIO 2

6Casio 3 + P 4 + 10Co.

Phosphorus is highlighted in the form of vapors that are condensed in the receiver under water, while white phosphorus is formed.

When heated to 250-300 ° C without air access, white phosphorus turns into red.

Black phosphorus is obtained by prolonged heating of white phosphorus at very high pressure (200 ° C and 1200 MPa).

1.5 Application

Red phosphorus is used in the manufacture of matches (see Figure). It is part of a mixture applied to the side surface of the matchbox. The main component of the composition of the match head is Bertolet Salt KCLO 3. From the friction of the head of the match about the smear of the particle of phosphorus in the air flammable. As a result of the reaction of phosphorus oxidation, heat is highlighted, leading to the decomposition of the berthal salt.

KCL +.

The resulting oxygen contributes to the ignition of the match of the match.

Phosphorus is used in metallurgy. It is used to obtain conductors and is part of some metal materials, such as tin bronze.

Also phosphorus is used in the production of phosphoric acid and pesticides (dichlorophos, chlorophos, etc.).

White phosphorus is used to create chimneys, as it is formed white smoke during its combustion.

ChapterII.. Phosphorus compounds

2.1 Oxides

Phosphorus forms several oxides. The most important of these are phosphorus oxide (V) P 4 O 10 and phosphorus oxide (III) P 4 O 6. Often their formulas are written in a simplified form - P 2 O 5 and P 2 O 3. In the structure of these oxides, the tetrahedral arrangement of phosphorus atoms is preserved.

Phosphorus oxide (III) P 4 O 6 is a waxy crystalline mass, melting at 22.5 ° C and turning into a colorless liquid. Poisonous.

When dissolved in cold water, phosphorous acid forms:

P 4 O 6 + 6H 2 O \u003d 4H 3 PO 3,

and when reactions with alkalis - the corresponding salts (phosphites).

Strong reducing agent. When interacting with oxygen is oxidized to P 4 O 10.

Phosphorus (III) oxide is obtained by oxidation of white phosphorus with a lack of oxygen.

Phosphorus oxide (V) P 4 O 10 - white crystalline powder. The reaches temperature is 36 ° C. It has several modifications, one of which (the so-called volatile) has the composition of P 4 O 10. The crystal lattice of this modification is composed of molecules P 4 O 10, interconnected by weak intermolecular forces, easily tearing when heated. Hence the volatility of this variety. Other polymer modifications. They are formed by endless layers of PO 4 tetrahedra.

When interacting, P 4 O 10 with water is formed phosphoric acid:

P 4 O 10 + 6H 2 O \u003d 4H 3 PO 4.

Being acid oxide, P 4 O 10 enters the reaction with the main oxides and hydroxides.

It is formed with high-temperature oxidation of phosphorus in an excess of oxygen (dry air).

Due to the exceptional hygroscopicity, phosphorus oxide (V) is used in laboratory and industrial technique as a drying and dehydrating agent. In its drying action, he surpasses all other substances. From anhydrous chlorine acid, chemically bound water takes on the formation of its anhydride:

4HCLO 4 + P 4 O 10 \u003d (HPO 3) 4 + 2Cl 2 O 7.

2.2 Acids and their salts

but) Phosphorous acid H 3 PO 3. Anhydrous phosphorous acid H 3 Po 3 forms the crystals with a density of 1.65 g / cm 3, melted at 74 ° C.

Structural formula:

.

When heated anhydrous H 3 PO 3, disproportionation (self-sextal self-seignment) is reactive:

4H 3 PO 3 \u003d pH 3 + 3H 3 PO 4.

Phosphorous acid salts - phosphites. For example, K 3 PO 3 (potassium phosphit) or Mg 3 (PO 3) 2 (magnesium phosphite).

H 3 PO 3 phosphorus acid is obtained by dissolving phosphorus oxide (III) or hydrolysis of phosphorus chloride (III) PCL 3:

PCL 3 + 3H 2 O \u003d H 3 PO 3 + 3HCl.

b) Phosphoric acid (orthophosphoric acid) H 3 PO 4.

Anhydrous phosphoric acid is bright transparent crystals, at room temperature spreading in air. Melting point 42.35 ° C. With water phosphate acid forms solutions of any concentrations.

Phosphorus was opened and highlighted in 1669 by the German chemist H. Brand. In nature, this element is found only in the form of connections. Main minerals - CA3 (PO4) 2 phosphorite and apatite 3CA3 (PO4) 2. CAF2 or CA5F (PO4) 3. In addition, the element is included in the protein, and also contains in the teeth and bones. Phosphorus easier interacts with oxygen and chlorine. In an excess of these substances, compounds of CO (for P) +5 are formed, and with a shortcoming - with a degree of oxidation +3. Phosphorus oxide can be represented by several formulas displaying different chemicals. Among them are the most common - it is P2O5 and P2O3. Other rare and poorly studied oxides include: P4O7, P4O8, P4O9, PO and P2O6.

The reaction of oxidation of elementary phosphorus oxygen proceeds slowly. Her various sides are interesting. First, in the dark, the glow is clearly visible to which it is accompanied. Secondly, the process of oxidation of this occurs always with the formation of ozone. This is due to the production of an intermediate compound - phosphoryl Po - according to the scheme: P + O2 → PO + O, and then: O + O2 → O3. Thirdly, oxidation is associated with a sharp change in the electrical conductivity of the surround air due to its ionization. Warming of light without noticeable warming, when leaked chemical reactionsis called chemiluminescence. In wet media, green chemiluminescence is due to the formation of the Po intermediate substance.

The oxidation of phosphorus proceeds only at a certain oxygen concentration. It should not be lower than the minimum and above maximum O2 thresholds. The interval itself depends on the temperatures and a number of other factors. For example, under standard conditions for oxidation, pure oxygen of phosphorus increases to reaching 300 mm Hg. Art. Then it decreases and falls almost to zero, when the partial oxygen pressure reaches 700 mm Hg. Art. and higher. Thus, oxide under normal conditions is not formed, since phosphorus is practically no oxidized.

Five-pointed phosphorus

The most characteristic oxidal is phosphoric anhydride, or phosphorus, P2O5. This is a white powder with a caustic smell. When determining in pairs of its molecular weight, it has been established that a more correct recording of its formula is P4O10. This is a non-combustible substance, it melts at a temperature of 565.6 C. Anhydride P2O5-Cylinder oxide with all the characteristic properties, but it eagerly absorbs moisture, therefore it is used as a dehumidifier of liquids or gases. Phosphorus oxide can take water that is part of chemical substances. Anhydride is formed as a result of the combustion of phosphorus in an oxygen or air atmosphere, with a sufficient amount of O2 according to the scheme: 4P + 5O2 → 2P2O5. It is used in the production of Acid H3PO4. When interacting with water, three acids can form:

• metaphosphorno: P2O5 + H2O → 2HPO3;
• pyrophosphorus: P2O5 + 2H2O → H4P2O7;
• orthophosphorus: P2O5 + 3H2O → 2H3PO4.

Five-pointed phosphorus thoroughly reacts with water and substances containing water, such as wood or cotton. At the same time, a large amount of heat is formed, which may even lead to a fire. It causes corrosion of metal and is very annoying (there are serious burns of eyes, skin) respiratory tracts and mucous membranes, even at such low concentrations, as 1 mg / m³.

Three-pointed phosphorus

Phosphorous anhydride, or phosphorus trioxide, P2O3 (P4O6) is a white crystalline substance (externally similar to wax), which melts at a temperature of 23.8 C and boils at a temperature of 173.7 C. Like P2O3 is a very poisonous substance. This is acidic oxide, with all the inherent properties. Phosphorus 3 oxide is formed due to the slow oxidation or combustion of the free substance (P) in the medium where the lack of oxygen takes place. Phosphorum trioxide slowly interacts with cold water, forming an acid: P2O3 + 3H2O → 2H3PO3. This phosphorus oxide reacts vigorously with hot waterAt the same time, the reactions proceed in different ways, as a result, a red phosphorus (allotropically modified chapels), phosphoroid hydride, and acids, can be formed, as well as acids: H3PO3 and H3PO4. The thermal decomposition of the P4O6 anhydride is accompanied by the cleavage of phosphorus atoms, the mixtures of oxides P4O7, P4O8, P4O9 are formed. In structure, they resemble P4O10. The most studied P4O8.

Phosphorus - element of the 3rd period and VA group Periodic system, Sequer number 15. Electronic formula of an atom [10 NE] 3S 2 3P 3, stable oxidation in compounds + v.

Phosphorus oxidation degrees scale:

Electricity of phosphorus (2.32) is significantly lower than typical non-metals, and slightly higher than in hydrogen. Forms various oxygen-containing acids, salts and binary compounds, manifests non-metallic (acid) properties. Most phosphates are insoluble in water.

In nature - thirteenth According to chemical prevalence, the element (sixth among non-metals) is found only in chemically associated. Vital element.

The lack of phosphorus in the soil is replenished with the introduction of phosphate fertilizers - mainly superphosphates.

Allotropic modifications of phosphorus

Red and White Phosphor R. It is known a few allotropic phosphorus forms in free form, the main is White phosphorus P 4 I. red phosphorus P n. In the reaction equations, allotropic forms are represented as P (Krasn.) And P (Bel.).

Red phosphorus consists of polymer molecules P n of different lengths. Amorphous, at room temperature slowly goes into white phosphorus. When heated to 416 ° C is removed (white phosphorus is condensed when the pair is cooled). Insoluble in organic solvents. Chemical activity is lower than that of white phosphorus. On the air lights up only when heated.

It is used as a reagent (safer than white phosphorus) in an inorganic synthesis, incandescent lamp filler, a component of the smear box in the manufacture of matches. Not poisonous.

White phosphorus consists of molecules P 4. Soft as wax (cutting with a knife). Melts and boils without decomposition (T PL 44.14 ° C, T Kip 287.3 ° C, p 1.82 g / cm 3). Oxisions in the air (green glow in the dark), with a large mass possible self-ignition. Special conditions are translated into red phosphorus. It is well soluble in benzene, ether, servo carbon. Does not react with water, stored under the water layer. Extremely chemically active. Shows redox properties. Restores noble metals from solutions of their salts.

It is used in the production of H 3 P0 4 and red phosphorus, as a reagent in organic synthesis, an alloy deoxidizer, an incerediary. Burning phosphorus should be extinguished by sand (but not water!). Extremely poisonous.

Equations of the most important phosphorus reactions:

Obtaining phosphorus industry

- Restoration of phosphorite hot coke (sand is added to calcium binding):

Ca 3 (PO4) 2 + 5C + 3SiO2 \u003d 3Casio3 + 2 R + 5CO (1000 ° С)

Phosphorus pairs are cooled and obtain solid white phosphorus.

Red phosphorus is prepared from white phosphorus (see above), depending on the conditions, the degree of polymerization N (P n) may be different.

Phosphorus compounds

Phosphine pH 3.. Binary connectionThe degree of oxidation of phosphorus is - III. Colorless gas with an unpleasant odor. The molecule has the structure of an unfinished tetrahedron [: P (H) 3] (SP 3-hybridization). A little soluble in water, does not react with it (unlike NH 3). Strong reducing agent, burns in air, oxidized in HNO 3 (conc.). Joins HI. It is used to synthesize phosphorodorganic connections. Strongly poisonous.

Equations of the most important phosphine reactions:

Obtaining phosphine B. laboratories:

SAZP2 + 6NSL (RSC) \u003d ZSASL + 2 RNZ

Phosphorus oxide (V) P 2 O 5. Acid oxide. White, thermally stable. In solid and gaseous states, Dimer P 4 O 10 with a structure of four tetrahedra associated with three vertines (P - O-P). With very high temperatures Monomerizes to P 2 O 5. There is also a glassy polymer (P 2 0 5) p. Extremely hygroscopic, reacts vigorously with water alkalis. Restored by white phosphorus. Takes water in oxygen-containing acids.

It is used as a very efficient dehydrating agent for draining solids, liquids and gas mixtures, the reagent in the production of phosphate glasses, the polymerization catalyst of alkenes. Poisonous.

Equations of the most important reactions of phosphorus oxide +5:

Getting: Infusion of phosphorus in excess of dry air.

Ortophosphoric acid H 3 P0 4. Oxoc acid. White substance, hygroscopic, finite product of interaction P 2 O 5 with water. The molecule has the structure of a distorted tetrahedron [P (O) (ON) 3] (SP 3-hybridizadium), contains covalent σ-bonds p - it and σ, π-bond p \u003d o. Melts without decomposition, with further heating decomposes. It is well soluble in water (548 g / 100 g H 2 0). Weak acid in solution is neutralized by alkalis, not completely - ammonia hydrate. Reacts with typical metals. Enters the reaction of ion exchange.

High-quality reaction is the loss of yellow silver orthophosphate (I). It is used in the production of mineral fertilizers, to clarify sucrose, as a catalyst in organic synthesis, the component of anti-corrosion coatings on cast iron and steel.

Equations of the most important reactions of orthophosphoric acid:

Obtaining phosphoric acid in industry:

boil phospheritan ore in sulfuric acid:

Ca3 (PO4) 2 + 3H2SO4 (conc.) \u003d 2 N3RO4. + 3Caso4

Sodium orthophosphate Na 3 PO 4. Oxosol. White, hygroscopic. Melts without decomposition, thermally stable. It is well soluble in water, hydrolyzed on the anion, creates a strongly high-alkaline medium in solution. Reacts in a solution with zinc and aluminum.

Enters the reaction of ion exchange.

Quality reaction to ion RO 4 3-

- the formation of a yellow precipitate of silver orthophosphate (I).

It is used to eliminate the "constant" stiffness of fresh water, as a component of detergents and photo beds, reagent in rubber synthesis. Equations of the most important reactions:

Getting: Complete neutralization H 3 P0 4 sodium hydroxide or by reaction:

Sodium hydroatophosphate Na 2 HPO 4. Acute oxosol. White, with moderate heating decomposes without melting. Well soluble in water, hydrolyzed by anion. Reacts with H 3 P0 4 (conc.), Neutralized by alkalis. Enters the reaction of ion exchange.

High-quality response to ion NRA 4 2-- the formation of a yellow precipitate of silver orthophosphate (I).

It is used as an emulsifier in condescending cow's milk, a component of food pasteurizers and photocurrents.

Equations of the most important reactions:

Obtaining: incomplete neutralization H 3 P0 4 sodium hydroxide in a diluted solution:

2NAOH + H3RO4 \u003d Na2HPO4 + 2H2O

Sodium Dihydroratophosphate NAH 2 PO 4. Acute oxosol. White, hygroscopic. With moderate heating decomposes without melting. Well soluble in water, anion H 2 P0 4 is subjected to a reversible dissociation. Neutralized by alkalis. Enters the reaction of ion exchange.

High-quality reaction to ion H 2 P0 4 - The formation of yellow silver orthophosphate (1).

It is used in glass production, to protect steel and cast iron from corrosion, like water softener.

Equations of the most important reactions:

Getting: Incomplete neutralization H 3 Po 4 caviar:

H3RO4 (conc.) + NaOH (RSC) \u003d NaH2PO4 + H2O.

Calcium Orthophosphate (PO 4) 2- Oxosol. White, refractory, thermally stable. Insoluble in water. Decompose concentrated acids. Restored by coke when fusing. The main component of phosphoritic ores (apatite, etc.).

It is used to obtain phosphorus, in the production of phosphate fertilizers (superphosphates), ceramics and glass, precipitated powder - as a component of the toothpaste and polymer stabilizer.

Equations of the most important reactions:

Phosphoric fertilizers

The mixture of sa (H 2 P0 4) 2 and CAS0 4 is called simple superphosphate, Sa (H 2 P0 4) 2 with admixture of Sunr0 4 - double superphosphate, they are easily absorbed by plants when feeding.

The most valuable fertilizers - ammophos. (contain nitrogen and phosphorus) are a mixture of ammonium acid salts NH 4 H 2 PO 4 and (NH 4) 2 HPO 4.

Phosphorus chloride (V) PCI5. Binary connection. White, volatile, thermally unstable. The molecule has the structure of the trigonal biiramid (SP 3 D-hybridization). In solid state, Dimer P 2 Cl 10 with the ionic structure of PCl 4 + [RSL 6] -. "Die" in wet air. Very reactive, completely hydrolyzed with water, reacts with alkalis. Restored by white phosphorus. It is used as a chlorineent in organic synthesis. Poisonous.

Equations of the most important reactions:

Getting: Chlorination of phosphorus.

Phosphorus oxides. Phosphorus forms several oxides. The most important of them are P4O6 and P4O10. Often their formulas are written in simplified form as P2O3 and P2O5 (the indices of the previous ones are divided into 2).

Phosphorus (III) oxide P4O6 is a waxy crystalline mass, melting at 22.5 ° C. It turns out of phosphorus incineration with a lack of oxygen. Strong reducing agent. Very poisonous.

Phosphorus oxide (V) P4O10 - white hygroscopic powder. It turns out when the phosphorus is burning in an excess of air or oxygen. It is very vigorously connected to water, and also takes water from other connections. It is used as a dry desiccant of gases and liquids.

Oxides and all oxygen compounds of phosphorus are much stronger than similar nitrogen compounds, which should be explained by the weakening of non-metallic properties in phosphorus compared to nitrogen.

Phosphorus oxide (V). P2O5 Energetically interacts with water, and also takes water from other connections. That is why P2O5 is widely used as a dryer various substances From vapor water.

Phosphoric anhydride, interacting with water, forms, primarily metaphosphoric acid NR3:

when boiling a solution of metaphosphoric acid, orthophosphoric acid H3PO4 is formed:

When heated H3PO4, H4P2O7 pyrophosphoric acid can be obtained:

P2O5 white synoda, greedily absorbed

it is used for drying gases and liquids, and in some cases

yach for cleavage of substances of chemically bound water:

2 NnO3 + P2O5 \u003d N2O5 + 2 nro3

4HCLO4 + P4O10 → (NR3) 4 + 2CL2O7.

Phosphorus oxide (V) is widely used in organic synthesis. He reacts with amides, turning them into nitrile:

P4O10 + RC (O) NH2 → P4O9 (OH) 2 + RCN

Carboxylic acids Translates into the appropriate anhydrides:

P4O10 + 12RCOOH → 4H3P04 + 6 (RCO) 2O

P2O5 + 6RCOOH → 2H3P04 + 3 (RCO) 2O

Also interacts with alcohols, ether, phenols and others organic compounds. At the same time there is a break p-O-P connections And phosphorian compounds are formed. Reacts with NH3 and with halogen hydrogen, forming ammonium phosphates and phosphorus oxygaloids:

P4O10 + 8PCl3 + O2 → 12CL3PO

When fushed P4O10 with basic oxides, various solid phosphates forms, the nature of which depends on the reaction conditions.

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