Calcium phosphate - main characteristics, properties and applications

Calcium hydrophosphate

(dicalcium phosphate, disubstituted calcium phosphate) is an inorganic substance, an acid salt of calcium and orthophosphoric acid with the formula CaHPO4. Forms crystalline hydrate. Fire and explosion proof.

Receipt[edit | edit code]

• The effect of sodium hydrogen phosphate on calcium chloride:

C a C l 2 + N a 2 HPO 4 → C a HPO 4 + 2 N a C l {\displaystyle {\mathsf {CaCl_{2}+Na_{2}HPO_{4}\ {\xrightarrow {\ }} \CaHPO_{4}+2\NaCl}}}

• The effect of orthophosphoric acid on calcium oxide or carbonate:

C a O + H 3 PO 4 → C a HPO 4 + H 2 O {\displaystyle {\mathsf {CaO+H_{3}PO_{4}\ {\xrightarrow {\ }}\ CaHPO_{4}+H_{ 2}O}}} C a CO 3 + H 3 PO 4 → C a HPO 4 + CO 2 ↑ + H 2 O {\displaystyle {\mathsf {CaCO_{3}+H_{3}PO_{4}\ { \xrightarrow {\ }}\CaHPO_{4}+CO_{2}\uparrow +H_{2}O}}}

• Decomposition of calcium dihydrogen orthophosphate:

C a ( H 2 PO 4 ) 2 ⇄ C a HPO 4 + H 3 PO 4 {\displaystyle {\mathsf {Ca(H_{2}PO_{4})_{2}\rightleftarrows \CaHPO_{4}+H_ {3}PO_{4}}}}

Properties of calcium phosphate

Physical properties

Calcium phosphate is a colorless or white crystalline substance (abrasive) that is extremely poorly soluble in water. It can exist in two modifications:

1. Monoclinic system.
2. Hexagonal system.

Easily reacts with acids, forming more soluble hydrophosphates.

Chemical properties

Calcium phosphate easily reacts with strong acids :

Ca3(PO4)2 + 3H2SO4 = 3CaSO4 + 2H3PO4

When exposed to temperature and (heating) - decomposes to form phosphorus oxide:

Ca3(PO4)2=P2O5+3CaO

It also reacts with salts to form an insoluble precipitate:

Ca3(PO4)2 + 3Li2SO4 = 2Li3PO4↓ + 3CaSO4

A reaction with nitric oxide with the participation of water is possible:

Ca3(PO4)2+ 3NO2 + H2O → Ca(NO3)2 + 2CaHPO4 + NO

At high temperatures (more than 1000 °C) it reacts with carbon :

Ca3(PO4)2 + 8C = Ca3P2 + 8CO

Chemical properties[edit | edit code]

• Crystalline hydrate and anhydrous calcium hydrogen phosphate are thermally unstable:

C a HPO 4 ⋅ 2 H 2 O → − H 2 O 100 o CC a HPO 4 → − H 2 O > 100 o CC a 2 P 2 O 7 {\displaystyle {\mathsf {CaHPO_{4}\cdot 2H_{ 2}O\ {\xrightarrow[{-H_{2}O}]{100^{o}C}}\ CaHPO_{4}\ {\xrightarrow[{-H_{2}O}]{>100^{ o}C}}\ Ca_{2}P_{2}O_{7}}}}

• Slowly absorbs ammonia from the air:

C a HPO 4 + NH 3 ⇄ ( NH 4 ) 2 HPO 4 + C a 3 ( PO 4 ) 2 {\displaystyle {\mathsf {CaHPO_{4}+NH_{3}\ \rightleftarrows \ (NH_{4}) _{2}HPO_{4}+Ca_{3}(PO_{4})_{2}}}}

Main characteristics

To understand the mechanism of calcium phosphate formation, you should familiarize yourself with its physical and chemical characteristics, the mass fraction of constituent substances, and the probability of decomposition under various circumstances. Graphic formulas and trivial names of salt are important.

Calcium phosphate is a white crystalline substance found in apatite. This is a mineral stone of the phosphate group, in which about 56% is calcium oxide. The properties of calcium phosphate are such that it does not dissolve well in water, and when exposed to acids it is converted into hydrophosphates. Chemical reactions can be written as equations and differ depending on the substance with which the phosphate compound reacts.

Its deposits are located on the territory of ancient seas. They are the result of the activity of phosphorobacteria. In some areas, the mineral is presented in the form of a mineral substance. Such deposits are widespread. They are actively involved in agriculture. Apatite is the basis for obtaining various raw materials:

• phosphate fertilizers;
• ceramics and glass;
• ferrous metallurgy products.

Phosphorites are natural minerals that differ in their origin. They are usually sedimentary. Phosphorites and apatites are very important for the national economy, as they make it possible to obtain fertilizer. As a source of the mineral calcium, it is used to feed cattle and poultry. There is feed calcium phosphate. It is produced in accordance with GOST requirements.

Apatite is of inorganic origin. It is used in many production processes. With its help you can get:

• free phosphorus;
• abrasive materials;
• ceramic and glass products.

Phosphates, like hydrogen phosphates and dihydrogen phosphates, are formed as a result of sequential dissociation. The experimental design is mastered by professional chemists. Specialists in this field study the properties of phosphates using professional tools and additional substances. School and university students also turn to the characteristics of a phosphate compound by solving problems in which, for example, they are asked to determine the oxidation state of elements, the solubility product, and how the constituent substances react to each other.

This substance is the basis of the E341 additive. In addition to substituted phosphorus salts, it contains calcium phosphate. To launch such a product on the market, it must be made in accordance with strict conditions.

Application[edit | edit code]

It is used for feeding livestock and as a phosphorus fertilizer. Also involved in the process of milk ripening during cheese production.

Registered as a food additive E341(ii).

Application

Calcium phosphate is actively used in many sectors of human life. It is often used as an additive in animal and poultry feed to compensate for calcium deficiency. It is added as a component to many drugs in pharmaceuticals and pharmacology. Also used in the production of glass and abrasives.

In the food industry, it received the code name – additive E341. It is used as a leavening agent, to fix color, and as a stabilizer.

Additive E431 is used in the production of milk powder, processed cheese, ice cream, bakery and liquor products, fish and meat products, sports nutrition, breakfast cereals, herbal teas, canned food, refined oils, baked goods and much more. Whether this food additive is beneficial or harmful for the human body cannot be said with certainty. Despite the fact that it is a component of bone tissue and is a source of calcium, some scientists are still actively talking about its harm, which can mainly be caused to the smooth functioning of the gastrointestinal tract.

In agriculture, it is effective as a mineral fertilizer, especially for acidic soils.

Many toothpastes and powders also contain calcium phosphate.

In order to obtain phosphorus, as well as phosphoric acid, it is used as the main raw material.

Calcium phosphate is also a building material for human bones and teeth.

Other phosphate compounds

In addition to calcium, there are formulas with aluminum, barium, iron, and sodium. Aluminum phosphate is a salt with a solid structure and a white tint. It is insoluble in water and is obtained by combining phosphoric acid and sodium aluminate. As a result, the desired salt is formed, as well as water and sodium hydroxide. In addition, there is a method in which aluminum sulfate and aluminum phosphate are mixed and then heated. The resulting material is used for the production of antacid drugs.

Barium phosphate has an amorphous form and is a white powder . It dissolves poorly in water, but by adding ammonium chloride, as well as any acid, it is possible to increase its solubility. To obtain such a compound, it is enough to add dihydrogen phosphate of this substance to barium hydroxide. There are other methods that have become more or less widespread in production. Barium phosphate is used to make special glass for measuring radiation levels. It also provides the basis for the production of phosphors.

Iron phosphate has the form of yellow crystals that do not dissolve in water. It is obtained by mixing sodium acetate with hydrogen phosphate of this mineral and an iron salt. The finished compound can be used to create drugs to combat molluscs, as well as homeopathic remedies used by people.

Sodium phosphate is presented in the form of white crystals that are hygroscopic. They dissolve perfectly in any liquid. To obtain this substance, reactions between sodium carbonate and phosphoric acid are carried out. This releases some carbon dioxide. Sodium phosphate is included in the E339 additive. When interacting with baking soda, it forms a leavening agent.

Calcium phosphate is widely used in the production of food additives. It is used to improve the characteristics of the test. The resulting composition is also suitable as a component of condensed milk and processed cheeses. It is also used as an emulsifier for sausage.

Excerpt describing calcium hydroxide phosphate

- I! I!.. - the prince said, as if awakening unpleasantly, without taking his eyes off the construction plan. - It is quite possible that the theater of war will come so close to us... - Ha ha ha! Theater of War! - said the prince. “I said and say that the theater of war is Poland, and the enemy will never penetrate further than the Neman. Desalles looked with surprise at the prince, who was talking about the Neman, when the enemy was already at the Dnieper; but Princess Marya, who had forgotten the geographical position of the Neman, thought that what her father said was true. - When the snow melts, they will drown in the swamps of Poland. “They just can’t see,” said the prince, apparently thinking about the campaign of 1807, which seemed so recent. “Bennigsen should have entered Prussia earlier, things would have taken a different turn...” “But, prince,” said Desalles timidly, “the letter talks about Vitebsk...” “Ah, in the letter, yes...” the prince said dissatisfied, “yes... yes...” “His face suddenly took on a gloomy expression. He paused. - Yes, he writes, the French are defeated, which river is this? Desalles lowered his eyes. “The prince doesn’t write anything about this,” he said quietly. - Doesn’t he write? Well, I didn’t make it up myself. - Everyone was silent for a long time. “Yes... yes... Well, Mikhaila Ivanovich,” he suddenly said, raising his head and pointing to the construction plan, “tell me how you want to redo it... Mikhail Ivanovich approached the plan, and the prince, having talked with him about the plan for the new building, angrily Having looked at Princess Marya and Desalles, he went to his room. Princess Marya saw Desalles' embarrassed and surprised gaze fixed on her father, noticed his silence and was amazed that the father had forgotten his son's letter on the table in the living room; but she was afraid not only to speak and ask Desalles about the reason for his embarrassment and silence, but she was afraid to even think about it. In the evening, Mikhail Ivanovich, sent from the prince, came to Princess Marya for a letter from Prince Andrei, which was forgotten in the living room. Princess Marya submitted the letter. Although it was unpleasant for her, she allowed herself to ask Mikhail Ivanovich what her father was doing. “They’re all busy,” said Mikhail Ivanovich with a respectfully mocking smile that made Princess Marya turn pale. – They are very worried about the new building. “We read a little, and now,” Mikhail Ivanovich said, lowering his voice, “the bureau must have started working on the will.” (Recently, one of the prince’s favorite pastimes was working on the papers that were supposed to remain after his death and which he called a will.) - And Alpatych is sent to Smolensk? - asked Princess Marya. - Why, he’s been waiting for a long time. When Mikhail Ivanovich returned with the letter to the office, the prince, wearing glasses, with a lampshade over his eyes and a candle, was sitting at the open bureau, with papers in his far-off hand, and in a somewhat solemn pose was reading his papers (remarks, as he called them), which were to be delivered to the sovereign after his death. When Mikhail Ivanovich entered, there were tears in his eyes, memories of the time when he wrote what he was now reading. He took the letter from Mikhail Ivanovich’s hands, put it in his pocket, put away the papers and called Alpatych, who had been waiting for a long time. On a piece of paper he wrote down what was needed in Smolensk, and he, walking around the room past Alpatych, who was waiting at the door, began to give orders. - First, postal paper, do you hear, eight hundred, according to the sample; gold-edged... a sample, so that it will certainly be according to it; varnish, sealing wax - according to a note from Mikhail Ivanovich. He walked around the room and looked at the memo. “Then personally give the governor a letter about the recording. Then they needed bolts for the doors of the new building, certainly of the style that the prince himself had invented. Then a binding box had to be ordered for storing the will. Giving orders to Alpatych lasted more than two hours. The prince still did not let him go. He sat down, thought and, closing his eyes, dozed off. Alpatych stirred. - Well, go, go; If you need anything, I will send it. Alpatych left. The prince went back to the bureau, looked into it, touched his papers with his hand, locked it again and sat down at the table to write a letter to the governor. It was already late when he stood up, sealing the letter. He wanted to sleep, but he knew that he would not fall asleep and that his worst thoughts came to him in bed. He called Tikhon and went with him through the rooms to tell him where to make his bed for that night. He walked around, trying on every corner. Everywhere he felt bad, but the worst thing was the familiar sofa in the office. This sofa was scary to him, probably because of the heavy thoughts that he changed his mind while lying on it. Nowhere was good, but the best place of all was the corner in the sofa behind the piano: he had never slept here before. Tikhon brought the bed with the waiter and began to set it up. - Not like that, not like that! - the prince shouted and moved it a quarter away from the corner, and then again closer. “Well, I’ve finally done everything over, now I’ll rest,” the prince thought and allowed Tikhon to undress himself. Frowning in annoyance from the efforts that had to be made to take off his caftan and trousers, the prince undressed, sank heavily onto the bed and seemed to be lost in thought, looking contemptuously at his yellow, withered legs. He didn’t think, but he hesitated in front of the difficulty ahead of him to lift those legs and move on the bed. “Oh, how hard it is! Oh, if only this work would end quickly, quickly, and you would let me go! - he thought. He pursed his lips and made this effort for the twentieth time and lay down. But as soon as he lay down, suddenly the whole bed moved evenly under him back and forth, as if breathing heavily and pushing. This happened to him almost every night. He opened his eyes that had closed. - No peace, damned ones! - he growled with anger at someone. “Yes, yes, there was something else important, I saved something very important for myself in bed at night. Valves? No, that's what he said. No, there was something in the living room. Princess Marya was lying about something. Desalle—that fool—was saying something. There’s something in my pocket, I don’t remember.”

Literature

• Chemical Encyclopedia / Editorial Board: Knunyants I.L. and others. - M.: Soviet Encyclopedia, 1988. - T. 1. - 623 p.
• [en.wikipedia.org/wiki/CRC_Handbook_of_Chemistry_and_Physics CRC Handbook of Chemistry and Physics]. — 89th Edition. - Taylor and Francis Group, LLC, 2008-2009.

To tie?

K:Wikipedia:Isolated articles (type: not specified)

Role in the human body

Calcium phosphate has a wide range of uses. Its special variety is hydroxyapatite. This compound is part of human bones and is a building material for them. The mineral is also present in tooth enamel in the form of fluorapatite. The need for phosphorus is small and amounts to 800−1500 mg. The absorption of a compound based on this mineral is regulated by the liver. This process is also influenced by vitamin D and hormones produced by the body.

Calcium phosphate is capable of reacting with food. In combination with other minerals it is capable of:

Phosphates are excreted in biological secretions in an amount of 4 grams. This happens every day. Obtaining calcium phosphate is possible in the laboratory. It is part of phosphorite. This substance originates in the earth's crust. There are natural sources for extracting the compound that serves as the basis for calcium phosphate using laboratory methods.

Calcium orthophosphate is produced by the reaction of orthophosphoric acid and calcium hydroxide. Subsequently, a series of processes are carried out, including filtration, subsequent drying and grinding. The molecular (structural) formula of calcium phosphate is designated as follows: Ca3 (PO4)2.

Key sources

Dairy products are unusually rich in calcium phosphate. It is also present in large quantities in the following products:

Salt is present in large quantities in goat milk. The compound is presented in the form of micelles. These are special particles whose core is reduced in size and is insoluble. It is surrounded by adsorbing ions and solvent molecules. Salt is a component of calcium caseinate, a component of milk that belongs to the group of phosphoproteins.

Despite such obvious benefits, experts recommend not allowing excess calcium phosphate in the daily menu. You should not take special supplements or fortified foods without a doctor’s prescription.

The ban is especially relevant for people with kidney stones and pathologies of the parathyroid glands. The same can be said for people being treated with tetracycline antibiotics.