Titanium oxides:
Ti (IV) - TiO 2 - Titanium dioxide. It has an amphoteric character. The most stable and has the greatest practical significance.
Ti (III) - Ti 2 O 3 - titanium oxide. Has a basic character. It is stable in solution and is a strong reducing agent, like other Ti(III) compounds.
TI (II) - TiO 2 - Titanium oxide. Has a basic character. Least stable.
Titanium dioxide, TiO2, is a compound of titanium with oxygen, in which titanium is tetravalent. White powder, yellow when heated. It is found in nature mainly in the form of the mineral rutile, temperature above 1850°. Density 3.9 - 4.25 g/cm3. Practically insoluble in alkalis and acids, with the exception of HF. In concentrated H 2 SO 4 dissolves only with prolonged heating. When titanium dioxide is fused with caustic or carbonic alkalis, titanates are formed, which are easily hydrolyzed in the cold to form orthotitanic acid (or hydrate) Ti (OH) 4, which is easily soluble in acids. When standing, it turns into mstatitanoic acid (form), which has a microcrystalline structure and is soluble only in hot concentrated sulfuric and hydrofluoric acids. Most titanates are practically insoluble in water. The basic properties of titanium dioxide are more pronounced than acidic ones, but salts in which titanium is a cation are also significantly hydrolyzed with the formation of the divalent titanyl radical TiO 2 +. The latter is included in the composition of salts as a cation (for example, titanyl sulfate TiOSO 4 * 2H 2 O). Titanium dioxide is one of the most important titanium compounds and serves as a starting material for the production of other titanium compounds, as well as partially metallic titanium. It is used mainly as a mineral paint, in addition as a filler in the production of rubber and plastic metals. Included in refractory glasses, glazes, and porcelain masses. Artificial precious stones, colorless and colored, are made from it.
Titanium dioxide is insoluble in water and dilute mineral acids (except hydrofluoric acid) and dilute alkali solutions.
Slowly dissolves in concentrated sulfuric acid:
TiO 2 + 2H 2 SO 4 = Ti (SO4) 2 + 2H 2 O
With hydrogen peroxide it forms orthotitanic acid H4TiO4:
TiO 2 + 2H 2 O 2 = H 4 TiO 4
In concentrated alkali solutions:
TiO 2 + 2NaOH = Na 2 TiO 3 + H 2 O
When heated, titanium dioxide and ammonia form titanium nitride:
2TiO 2 + 2NH 3 = 2TiN + 3H 2 O + O 2
In a saturated solution of potassium bicarbonate:
TiO 2 + 2KHCO 3 = K 2 TiO 3 + H 2 O + 2CO 2
When fused with oxides, hydroxides and carbonates, titanates and double oxides are formed:
TiO 2 + BaO = BaO TiO 2 (BaTiO 3)
TiO 2 + BaCO 3 = BaO TiO2 + CO 2 (BaTiO 3)
TiO 2 + Ba (OH) 2 = BaO TiO 2 (BaTiO 3)
Titanium hydroxides:
H 2 TiO 3 - P.R. = 1.0 10 -29
H 2 TiO 4 - P.R. = 3.6 10 -17
TIO (OH) 2 - P.R. = 1.0 10 -29
Ti (OH) 2 - P.R. = 1.0 10 -35
Hydrooxide Ti (IV) - Ti (OH) 4 or H 4 TiO 4 - orthotitanic acid apparently does not exist at all, and the precipitate that precipitates when bases are added to solutions of Ti (IV) salts is the hydrated form of TiO 2. This substance dissolves in concentrated alkalis, and from such solutions hydrated titanates can be isolated with the general formula: M 2 TiO 3 nH 2 O and M 2 Ti 2 O 5 nH 2 O.
Titanium is characterized by complex formation with the corresponding hydrohalic acids and especially with their salts. The most typical are complex derivatives with the general formula Me 2 TiG 6 (where Me is a monovalent metal). They crystallize well and undergo hydrolysis much less than the original TiG 4 halides. This indicates the stability of TiG 6 complex ions in solution.
The color of titanium derivatives strongly depends on the nature of the halogen they contain:
The stability of salts of complex acids of the H 2 EG 6 type, in general, increases in the Ti-Zr-Hf series and decreases in the F-Cl-Br-I halogen series.
Derivatives of trivalent elements are more or less characteristic only of titanium. Dark purple oxide Ti 2 O 3 (mp 1820°C) can be obtained by calcining TiO 2 to 1200°C in a stream of hydrogen. Blue Ti 2 O 3 is formed as an intermediate product at 700-1000°C.
Ti 2 O 3 is practically insoluble in water. Its hydroxide is formed in the form of a dark brown precipitate when alkalis act on solutions of trivalent titanium salts. It begins to precipitate from acidic solutions at pH = 4, has only basic properties and does not dissolve in excess alkali. However, metal titanites (Li, Na, Mg, Mn) produced from HTiO 2 were obtained dry. Blue-black “titanium bronze” of composition Na0.2TiO 2 is also known.
Titanium (III) hydroxide is easily oxidized by atmospheric oxygen. If there are no other substances capable of oxidation in the solution, hydrogen peroxide is formed simultaneously with the oxidation of Ti (OH) 3. In the presence of Ca (OH) 2 (binding H 2 O 2), the reaction proceeds according to the equation:
2Ti (OH) 3 + O 2 + 2H 2 O = 2Ti (OH) 4 + H 2 O 2
Nitrate salts Ti (OH) 3 are reduced to ammonia.
Purple TiCl 3 powder can be obtained by passing a mixture of TiCl 4 vapor with excess hydrogen through a tube heated to 650°C. Heating causes its sublimation (with the partial formation of dimer Ti 2 Cl 6 molecules) and then dismutation according to the scheme:
2TiCl 3 = TiCl 4 + TiCl 2
It is interesting that even under normal conditions, titanium tetrachloride is gradually reduced by metallic copper, forming a black compound of the composition CuTiCl 4 (i.e. CuCl·TiCl 3).
Titanium trichloride is also formed by the action of hydrogen on TiCl 4 at the time of release (Zn + acid). In this case, the colorless solution turns purple, characteristic of Ti 3+ ions, and a crystal hydrate of the composition TiCl 3 ·6H 2 O can be isolated from it. A low-stable green crystal hydrate of the same composition is also known, released from a TiCl 3 solution saturated with HCl. The structure of both forms, as well as similar crystal hydrates of CrCl 3, corresponds to the formulas Cl 3 and Cl 2H 2 O. When standing in an open vessel, the TiCl 3 solution gradually becomes discolored due to the oxidation of Ti 3+ to Ti 4+ by atmospheric oxygen according to the reaction:
4TiCl 3 + O 2 + 2H 2 O = 4TiOCl 2 + 4HCl.
Ti3+ ion is one of the very few reducing agents that quite quickly reduce (in an acidic environment) perchlorates to chlorides. In the presence of platinum, Ti 3+ is oxidized by water (with the release of hydrogen).
Anhydrous Ti 2 (SO 4) 3 is green in color. It is insoluble in water, and its solution in dilute sulfuric acid has the violet color usual for Ti 3+ salts. From trivalent titanium sulfate, complex salts are produced, mainly of the types Me · 12H 2 O (where Me is Cs or Rb) and Me (with a variable content of water of crystallization depending on the nature of the cation).
The heat of formation of TiO (mp 1750°C) is 518 kJ/mol. It is obtained in the form of a golden-yellow compact mass by heating a compressed TiO 2 + Ti mixture in a vacuum to 1700°C. An interesting way of its formation is the thermal decomposition (in a high vacuum at 1000°C) of titanyl nitrile.
Similar in appearance to metal, dark brown TiS is obtained by calcining TiS 2 in a stream of hydrogen (initially, sulfides of intermediate composition are formed, in particular Ti 2 S 3). TiSe, TiTe and silicide of the composition Ti 2 Si are also known.
All TiG 2 are formed by heating the corresponding TiG 3 halides without air access due to their decomposition according to the following scheme:
2TiG 3 =TiG 4 +TiG 2
At slightly higher temperatures, the TiG 2 halides themselves undergo dismutation according to the scheme: 2TiG 2 = TiG 4 + Ti
Titanium dichloride can also be obtained by reducing TiCl4 with hydrogen at 700°C. It is highly soluble in water (and alcohol), and with liquid ammonia it gives gray ammonia TiCl 2 4NH 3 . A TiCl 2 solution can be prepared by reducing TiCl 4 with sodium amalgam. As a result of oxidation by atmospheric oxygen, the colorless TiCl 2 solution quickly turns brown, then becomes violet (Ti 3+) and, finally, becomes discolored again (Ti 4+). The black precipitate of Ti (OH) 2 obtained by the action of alkali on a TiCl 2 solution is extremely easily oxidized.
Titanium(III) hydroxide- inorganic compound, titanium metal hydroxide with the formula Ti(OH) 3, brown-violet precipitate, insoluble in water.
Receipt
- Formed by treating solutions of trivalent titanium salts with alkalis at pH = 4:
texvc not found; See math/README for setup help.: \mathsf(TiCl_3 + 3NaOH \ \xrightarrow()\ Ti(OH)_3\downarrow + 3NaCl )
Unable to parse expression (Executable file texvc not found; See math/README for setup help.: \mathsf(Ti_2(SO_4)_3 + 6KOH \ \xrightarrow()\ 2Ti(OH)_3\downarrow + 3K_2SO_4 )
Physical properties
Titanium(III) hydroxide forms a brownish-violet precipitate that gradually turns white due to oxidation.
Chemical properties
- Easily oxidized:
texvc not found; See math/README for setup help.): \mathsf(4Ti(OH)_3 + O_2 + 2H_2O \ \xrightarrow()\ 4H_4TiO_4 )
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Literature
- Chemical Encyclopedia / Editorial Board: Knunyants I.L. and others. - M.: Soviet Encyclopedia, 1995. - T. 4. - 639 p. - ISBN 5-82270-092-4.
- Chemist's Handbook / Editorial Board: Nikolsky B.P. and others. - 3rd ed., rev. - L.: Chemistry, 1971. - T. 2. - 1168 p.
- Ripan R., Ceteanu I. Inorganic chemistry. Chemistry of metals. - M.: Mir, 1972. - T. 2. - 871 p.
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Excerpt characterizing Titanium(III) Hydroxide
The books in the room spun like a whirlwind and fell together on the floor. It seemed as if a typhoon was raging inside this strange man. But then I, too, became indignant and slowly said:“If you don’t calm down right now, I’ll leave the contact, and you can continue to rebel alone if it gives you so much pleasure.”
The man was clearly surprised, but “cooled down” a little. It seemed that he was not used to not being obeyed immediately as soon as he “expressed” any of his desires. I never liked people of this type - neither then nor when I became an adult. I have always been outraged by rudeness, even if, as in this case, it came from a dead person...
My violent guest seemed to calm down and asked in a more normal voice if I wanted to help him? I said yes, if he promises to behave normally. Then he said that he absolutely needed to talk to his wife, and that he would not leave (the earth) until he could “get through” to her. I naively thought that this was one of those options when a husband loved his wife very much (despite how wild it looked to him) and decided to help, even if I didn’t like him very much. We agreed that he would return to me tomorrow, when I would not be at home and I would try to do everything I could for him.
The next day, from the very morning I felt his crazy (I can’t call it anything else) presence. I mentally sent him a signal that I couldn’t rush things and would leave the house when I could, so as not to raise unnecessary questions among my family. But that was not the case... My new acquaintance was again completely unbearable, apparently the opportunity to talk to his wife again made him simply insane. Then I decided to rush things and get rid of him as soon as possible. Usually I tried not to refuse help to anyone, so I did not refuse this strange, eccentric entity. I told my grandmother that I wanted to take a walk and went out into the yard.
“Well, lead the way,” I mentally said to my companion.
We walked for about ten minutes. His house was on a parallel street, very close to us, but for some reason I didn’t remember this man at all, although I seemed to know all my neighbors. I asked how long ago he died? He said that it had been ten years already (!!!)... It was completely impossible, and in my opinion it was too long ago!
“But how can you still be here?” – I asked dumbfounded.
“I told you, I won’t leave until I talk to her!” – he answered irritably.
Something was wrong here, but I couldn’t figure out what. Of all my dead “guests,” not one was here on earth for so long. Perhaps I was wrong, and this strange man loved his wife so much that he could not bring himself to leave her?.. Although, to be honest, for some reason I had great difficulty believing this. Well, he didn’t look like an “eternally in love knight”, even with great stretch... We approached the house... and then I suddenly felt that my stranger was timid.
- Well, shall we go? – I asked.
“You don’t know my name,” he muttered.
“You should have thought about this at the beginning,” I answered.
Then suddenly it was as if some kind of door opened in my memory - I remembered what I knew about these neighbors...
It was quite a “famous” house for its oddities (which, in my opinion, only I believed in in our entire district) house. There were rumors among the neighbors that the owner was apparently not completely normal, since she constantly told some “wild” stories with objects flying in the air, writing pens, ghosts, etc. etc... (similar things are shown very well in the film "Ghost", which I saw many years later).
The neighbor was a very pleasant woman of about forty-five, whose husband actually died about ten years ago. And from then on, all these incredible miracles began in her house. I visited her several times, eager to find out what was going on there, but, unfortunately, I was never able to get my reticent neighbor to talk. Therefore, now I completely shared the impatience of her strange husband and hurried to enter as quickly as possible, anticipating in advance what, according to my ideas, was supposed to happen there.
“My name is Vlad,” my former neighbor croaked.
I looked at him in surprise and realized that he was very afraid... But I decided not to pay attention to it and entered the house. A neighbor was sitting by the fireplace embroidering a pillow. I said hello and was about to explain why I came here, when she suddenly said quickly:
- Please, honey, leave quickly! It can be dangerous here.
The poor woman was scared half to death, and I suddenly understood what she was so afraid of... She apparently always felt the presence of her husband when he came to her!.. And all the poltergeist manifestations that had happened to her before apparently occurred through his fault. Therefore, again feeling his presence, the poor woman just wanted to “protect” me from possible shock... I gently took her hands and said as softly as possible:
– I know what you are afraid of. Please listen to what I have to say and this will all end forever.
I tried to explain to her as best I could about the souls coming to me and how I was trying to help them all. I saw that she believed me, but for some reason she was afraid to show it to me.
Titanium oxides:
Ti(IV) – TiO2– Titanium dioxide. It has an amphoteric character. The most stable and has the greatest practical significance.
Ti(III) – Ti 2 O 3– titanium oxide. Has a basic character. It is stable in solution and is a strong reducing agent, like other Ti(III) compounds.
TI(II) – TiO 2- Titanium oxide. Has a basic character. Least stable.
Titanium dioxide, TiO2, is a compound of titanium with oxygen, in which titanium is tetravalent. White powder, yellow when heated. It is found in nature mainly in the form of the mineral rutile, temperature above 1850°. Density 3.9 - 4.25 g/cm3. Practically insoluble in alkalis and acids, with the exception of HF. In concentrated H 2 SO 4 dissolves only with prolonged heating. When titanium dioxide is fused with caustic or carbonic alkalis, titanates are formed, which are easily hydrolyzed in the cold to form orthotitanic acid (or hydrate) Ti(OH) 4, which is easily soluble in acids. When standing, it turns into mstatitanoic acid (form), which has a microcrystalline structure and is soluble only in hot concentrated sulfuric and hydrofluoric acids. Most titanates are practically insoluble in water. The basic properties of titanium dioxide are more pronounced than acidic ones, but salts in which titanium is a cation are also significantly hydrolyzed with the formation of the divalent titanyl radical TiO 2 +. The latter is included in the composition of salts as a cation (for example, titanyl sulfate TiOSO 4 * 2H 2 O). Titanium dioxide is one of the most important titanium compounds and serves as a starting material for the production of other titanium compounds, as well as partially metallic titanium. It is used mainly as a mineral paint, in addition as a filler in the production of rubber and plastic metals. Included in refractory glasses, glazes, and porcelain masses. Artificial precious stones, colorless and colored, are made from it.
Titanium dioxide is insoluble in water and dilute mineral acids (except hydrofluoric acid) and dilute alkali solutions.
Slowly dissolves in concentrated sulfuric acid:
TiO 2 + 2H 2 SO 4 = Ti(SO4) 2 + 2H 2 O
With hydrogen peroxide it forms orthotitanic acid H4TiO4:
TiO 2 + 2H 2 O 2 = H 4 TiO 4
In concentrated alkali solutions:
TiO 2 + 2NaOH = Na 2 TiO 3 + H 2 O
When heated, titanium dioxide and ammonia form titanium nitride:
2TiO 2 + 2NH 3 = 2TiN + 3H 2 O + O 2
In a saturated solution of potassium bicarbonate:
TiO 2 + 2KHCO 3 = K 2 TiO 3 + H 2 O + 2CO 2
When fused with oxides, hydroxides and carbonates, titanates and double oxides are formed:
TiO 2 + BaO = BaO∙TiO 2 (BaTiO 3)
TiO 2 + BaCO 3 = BaO∙TiO2 + CO 2 (BaTiO 3)
TiO 2 + Ba(OH) 2 = BaO∙TiO 2 (BaTiO 3)
Titanium hydroxides:
H 2 TiO 3 – P.R. = 1.0∙10 -29
H 2 TiO 4 - P.R. = 3.6∙10 -17
TIO(OH) 2 - P.R. = 1.0∙10 -29
Ti(OH) 2 - P.R. = 1.0∙10 -35
Hydrooxide Ti(IV) - Ti(OH) 4 or H 4 TiO 4 - orthotitanic acid apparently does not exist at all, and the precipitate that precipitates when bases are added to solutions of Ti(IV) salts is a hydrated form of TiO 2. This substance dissolves in concentrated alkalis, and from such solutions hydrated titanates of the general formula can be isolated: M 2 TiO 3 ∙nH 2 O and M 2 Ti 2 O 5 ∙nH 2 O.
Titanium is characterized by complex formation with the corresponding hydrohalic acids and especially with their salts. The most typical are complex derivatives with the general formula Me 2 TiG 6 (where Me is a monovalent metal). They crystallize well and undergo hydrolysis much less than the original TiG 4 halides. This indicates the stability of TiG 6 complex ions in solution.
The color of titanium derivatives strongly depends on the nature of the halogen they contain:
The stability of salts of complex acids of the H 2 EG 6 type, in general, increases in the Ti-Zr-Hf series and decreases in the F-Cl-Br-I halogen series.
Derivatives of trivalent elements are more or less characteristic only of titanium. Dark purple oxide Ti 2 O 3 (mp 1820 °C) can be obtained by calcining TiO 2 to 1200 °C in a stream of hydrogen. Blue Ti 2 O 3 is formed as an intermediate product at 700-1000 ° C.
Ti 2 O 3 is practically insoluble in water. Its hydroxide is formed in the form of a dark brown precipitate when alkalis act on solutions of trivalent titanium salts. It begins to precipitate from acidic solutions at pH = 4, has only basic properties and does not dissolve in excess alkali. However, metal titanites (Li, Na, Mg, Mn) produced from HTiO 2 were obtained dry. Blue-black “titanium bronze” of the composition Na0.2TiO 2 is also known.
Titanium (III) hydroxide is easily oxidized by atmospheric oxygen. If there are no other substances capable of oxidation in the solution, hydrogen peroxide is formed simultaneously with the oxidation of Ti(OH) 3. In the presence of Ca(OH) 2 (binding H 2 O 2), the reaction proceeds according to the equation:
2Ti(OH) 3 + O 2 + 2H 2 O = 2Ti(OH) 4 + H 2 O 2
Nitrate salts Ti(OH) 3 are reduced to ammonia.
Purple TiCl 3 powder can be obtained by passing a mixture of TiCl 4 vapor with excess hydrogen through a tube heated to 650 °C. Heating causes its sublimation (with the partial formation of dimer Ti 2 Cl 6 molecules) and then dismutation according to the scheme:
2TiCl 3 = TiCl 4 + TiCl 2
It is interesting that even under normal conditions, titanium tetrachloride is gradually reduced by metallic copper, forming a black compound of the composition CuTiCl 4 (i.e. CuCl·TiCl 3).
Titanium trichloride is also formed by the action of hydrogen on TiCl 4 at the time of release (Zn + acid). In this case, the colorless solution turns purple, characteristic of Ti 3+ ions, and a crystal hydrate of the composition TiCl 3 ·6H 2 O can be isolated from it. A low-stable green crystal hydrate of the same composition is also known, released from a TiCl 3 solution saturated with HCl. The structure of both forms, as well as similar crystalline hydrates of CrCl 3, correspond to the formulas Cl 3 and Cl 2H 2 O. When standing in an open vessel, the TiCl 3 solution gradually becomes discolored due to the oxidation of Ti 3+ to Ti 4+ by atmospheric oxygen according to the reaction:
4TiCl 3 + O 2 + 2H 2 O = 4TiOCl 2 + 4HCl.
Ti3+ ion is one of the very few reducing agents that quite quickly reduce (in an acidic environment) perchlorates to chlorides. In the presence of platinum, Ti 3+ is oxidized by water (with the release of hydrogen).
Anhydrous Ti 2 (SO 4) 3 is green in color. It is insoluble in water, and its solution in dilute sulfuric acid has the violet color usual for Ti 3+ salts. From trivalent titanium sulfate, complex salts are produced, mainly of the types Me·12H 2 O (where Me is Cs or Rb) and Me (with a variable content of water of crystallization depending on the nature of the cation).
The heat of formation of TiO (mp 1750 °C) is 518 kJ/mol. It is obtained in the form of a golden-yellow compact mass by heating a compressed TiO 2 + Ti mixture in a vacuum to 1700 °C. An interesting way of its formation is the thermal decomposition (in a high vacuum at 1000 °C) of titanyl nitrile. Similar in appearance to metal, dark brown TiS is obtained by calcining TiS 2 in a stream of hydrogen (initially, sulfides of intermediate composition are formed, in particular Ti 2 S 3). TiSe, TiTe and silicide of the composition Ti 2 Si are also known.
All TiG 2 are formed by heating the corresponding TiG 3 halides without air access due to their decomposition according to the following scheme:
2TiG 3 = TiG 4 + TiG 2
At slightly higher temperatures, the TiG 2 halides themselves undergo dismutation according to the scheme: 2TiG 2 = TiG 4 + Ti. Titanium dichloride can also be obtained by reducing TiCl4 with hydrogen at 700 °C. It is highly soluble in water (and alcohol), and with liquid ammonia it gives gray ammonia TiCl 2 4NH 3 . A TiCl 2 solution can be prepared by reducing TiCl 4 with sodium amalgam. As a result of oxidation by atmospheric oxygen, the colorless TiCl 2 solution quickly turns brown, then becomes violet (Ti 3+) and, finally, becomes discolored again (Ti 4+). The black precipitate of Ti(OH) 2 obtained by the action of alkali on a TiCl 2 solution is extremely easily oxidized.
Titanium(II) hydroxide- inorganic compound titanium metal hydroxide with the formula Ti(OH) 2, black powder, insoluble in water.
Receipt
- Treatment of solutions of divalent titanium halides with alkalis:
Physical properties
Titanium(II) hydroxide forms a black precipitate that gradually becomes lighter due to decomposition.
Chemical properties
- Decomposes when stored in the presence of water:
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Literature
- Chemical Encyclopedia / Editorial Board: Knunyants I.L. and others. - M.: Soviet Encyclopedia, 1995. - T. 4. - 639 p. - ISBN 5-82270-092-4.
- Chemist's Handbook / Editorial Board: Nikolsky B.P. and others. - 3rd ed., rev. - L.: Chemistry, 1971. - T. 2. - 1168 p.
- Ripan R., Ceteanu I. Inorganic chemistry. Chemistry of metals. - M.: Mir, 1972. - T. 2. - 871 p.
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| This is a draft article about inorganic matter. You can help the project by adding to it. |
Excerpt characterizing Titanium(II) Hydroxide
The beauty went to her aunt, but Anna Pavlovna still kept Pierre close to her, appearing as if she had one last necessary order to make.– Isn’t she amazing? - she said to Pierre, pointing to the majestic beauty sailing away. - Et quelle tenue! [And how she holds herself!] For such a young girl and such tact, such a masterful ability to hold herself! It comes from the heart! Happy will be the one whose it will be! With her, the most unsecular husband will involuntarily occupy the most brilliant place in the world. Isn't it true? I just wanted to know your opinion,” and Anna Pavlovna released Pierre.
Pierre sincerely answered Anna Pavlovna in the affirmative to her question about Helen’s art of holding herself. If he ever thought about Helen, he thought specifically about her beauty and about her unusual calm ability to be silently worthy in the world.
Auntie accepted two young people into her corner, but it seemed that she wanted to hide her adoration for Helen and wanted to more express her fear of Anna Pavlovna. She looked at her niece, as if asking what she should do with these people. Moving away from them, Anna Pavlovna again touched Pierre’s sleeve with her finger and said:
- J"espere, que vous ne direz plus qu"on s"ennuie chez moi, [I hope you won’t say another time that I’m bored] - and looked at Helen.
Helen smiled with an expression that said that she did not admit the possibility that anyone could see her and not be admired. Auntie cleared her throat, swallowed her drool and said in French that she was very glad to see Helen; then she turned to Pierre with the same greeting and with the same mien. In the middle of a boring and stumbling conversation, Helen looked back at Pierre and smiled at him with that clear, beautiful smile with which she smiled at everyone. Pierre was so used to this smile, it expressed so little for him that he did not pay any attention to it. Auntie was talking at this time about the collection of snuff boxes that Pierre’s late father, Count Bezukhy, had, and showed her snuff box. Princess Helen asked to see the portrait of her aunt's husband, which was made on this snuff box.
“This was probably done by Vines,” said Pierre, naming the famous miniaturist, bending over to the table to pick up a snuffbox, and listening to the conversation at another table.
He stood up, wanting to go around, but the aunt handed the snuff-box right across Helen, behind her. Helen leaned forward to make room and looked back, smiling. She was, as always at evenings, in a dress that was very open in front and back, according to the fashion of that time. Her bust, which always seemed marble to Pierre, was at such a close distance from his eyes that with his myopic eyes he involuntarily discerned the living beauty of her shoulders and neck, and so close to his lips that he had to bend down a little to touch her. He heard the warmth of her body, the smell of perfume and the creak of her corset as she moved. He did not see her marble beauty, which was one with her dress, he saw and felt all the charm of her body, which was covered only by clothes. And, once he saw this, he could not see otherwise, just as we cannot return to a deception once explained.
“So you haven’t noticed how beautiful I am until now? – Helen seemed to say. “Have you noticed that I’m a woman?” Yes, I am a woman who can belong to anyone and you too,” said her look. And at that very moment Pierre felt that Helen not only could, but had to be his wife, that it could not be otherwise.
He knew it at that moment as surely as he would have known it standing under the aisle with her. How will it be? and when? he didn't know; he didn’t even know whether it would be good (he even felt that it was not good for some reason), but he knew that it would be.
Pierre lowered his eyes, raised them again and again wanted to see her as such a distant, alien beauty as he had seen her every day before; but he could no longer do this. He could not, just as a person who had previously looked in the fog at a blade of weeds and saw a tree in it, cannot, after seeing the blade of grass, again see a tree in it. She was terribly close to him. She already had power over him. And between him and her there were no longer any barriers, except for the barriers of his own will.
- Bon, je vous laisse dans votre petit coin. Je vois, que vous y etes tres bien, [Okay, I'll leave you in your corner. I see you feel good there,” said Anna Pavlovna’s voice.
And Pierre, with fear remembering whether he had done something reprehensible, blushing, looked around him. It seemed to him that everyone knew, just like him, about what happened to him.
After a while, when he approached the large circle, Anna Pavlovna said to him:
– On dit que vous embellissez votre maison de Petersbourg. [They say you are decorating your St. Petersburg house.]
(It was true: the architect said that he needed it, and Pierre, without knowing why, was decorating his huge house in St. Petersburg.)
“C"est bien, mais ne demenagez pas de chez le prince Vasile. Il est bon d"avoir un ami comme le prince,” she said, smiling at Prince Vasily. - J"en sais quelque chose. N"est ce pas? [That's good, but don't move away from Prince Vasily. It's good to have such a friend. I know something about this. Isn't that right?] And you are still so young. You need advice. Don't be angry with me for taking advantage of old women's rights. “She fell silent, as women always remain silent, expecting something after they tell you about their years. – If you get married, then it’s a different matter. – And she combined them into one look. Pierre did not look at Helen, and she did not look at him. But she was still terribly close to him. He mumbled something and blushed.
Titanium oxides:
Ti(IV) –TiO 2 – Titanium dioxide. It has an amphoteric character. The most stable and has the greatest practical significance.
Ti(III) –Ti 2 O 3 – titanium oxide. Has a basic character. It is stable in solution and is a strong reducing agent, like other Ti(III) compounds.
TI(II) –TiO 2 - Titanium oxide. Has a basic character. Least stable.
Titanium dioxide, TiO2, is a compound of titanium with oxygen, in which titanium is tetravalent. White powder, yellow when heated. It is found in nature mainly in the form of the mineral rutile, temperature above 1850°. Density 3.9 - 4.25 g/cm3. Practically insoluble in alkalis and acids, with the exception of HF. In concentrated H 2 SO 4 dissolves only with prolonged heating. When titanium dioxide is fused with caustic or carbonic alkalis, titanates are formed, which are easily hydrolyzed in the cold to form orthotitanic acid (or hydrate)Ti(OH) 4, which is easily soluble in acids. When standing, it turns into mstatitanoic acid (form), which has a microcrystalline structure and is soluble only in hot concentrated sulfuric and hydrofluoric acids. Most titanates are practically insoluble in water. The basic properties of titanium dioxide are more pronounced than acidic ones, but salts in which titanium is a cation are also significantly hydrolyzed with the formation of the divalent titanyl radical TiO 2 +. The latter is included in the composition of salts as a cation (for example, titanium sulfate TiOSO 4 * 2H 2 O). Titanium dioxide is one of the most important titanium compounds and serves as a starting material for the production of other titanium compounds, as well as partially metallic titanium. It is used mainly as a mineral paint, in addition as a filler in the production of rubber and plastic metals. Included in refractory glasses, glazes, and porcelain masses. Artificial precious stones, colorless and colored, are made from it.
Titanium dioxide is insoluble in water and dilute mineral acids (except hydrofluoric acid) and dilute alkali solutions.
Slowly dissolves in concentrated sulfuric acid:
TiO 2 + 2H 2 SO 4 = Ti(SO4) 2 + 2H 2 O
With hydrogen peroxide it forms orthotitanic acid H4TiO4:
TiO 2 + 2H 2 O 2 = H 4 TiO 4
In concentrated alkali solutions:
TiO 2 + 2NaOH = Na 2 TiO 3 + H 2 O
When heated, titanium dioxide and ammonia form titanium nitride:
2TiO 2 + 2NH 3 = 2TiN + 3H 2 O + O 2
In a saturated solution of potassium bicarbonate:
TiO 2 + 2KHCO 3 = K 2 TiO 3 + H 2 O + 2CO 2
When fused with oxides, hydroxides and carbonates, titanates and double oxides are formed:
TiO 2 + BaO = BaO∙TiO 2 (BaTiO 3)
TiO 2 + BaCO 3 = BaO∙TiO2 + CO 2 (BaTiO 3)
TiO 2 + Ba(OH) 2 = BaO∙TiO 2 (BaTiO 3)
Titanium hydroxides:
H 2 TiO 3 – P.R. = 1.0∙10 -29
H 2 TiO 4 - P.R. = 3.6∙10 -17
TIO(OH) 2 - P.R. = 1.0∙10 -29
Ti(OH) 2 - P.R. = 1.0∙10 -35
The hydroxide Ti(IV) –Ti(OH) 4 or H 4 TiO 4 - orthotitanic acid apparently does not exist at all, and the precipitate that precipitates when bases are added to solutions of Ti(IV) salts is the hydrated form of TiO 2. This substance dissolves in concentrated alkalis, and from such solutions hydrated titanates of the general formula can be isolated: M 2 TiO 3 ∙nH 2 O and M 2 Ti 2 O 5 ∙nH 2 O.
Titanium is characterized by complex formation with the corresponding hydrohalic acids and especially with their salts. The most typical are complex derivatives with the general formula Me 2 TiG 6 (where Me is a monovalent metal). They crystallize well and undergo hydrolysis much less than the original TiG 4 halides. This indicates the stability of TiG 6 complex ions in solution.
The color of titanium derivatives strongly depends on the nature of the halogen they contain:
The stability of salts of complex acids of the H 2 EG 6 type, in general, increases in the Ti-Zr-Hf series and decreases in the F-Cl-Br-I halogen series.
Derivatives of trivalent elements are more or less characteristic only of titanium. Dark purple oxide Ti 2 O 3 (mp 1820 °C) can be obtained by calcining TiO 2 to 1200 °C in a stream of hydrogen. Blue Ti 2 O 3 is formed as an intermediate product at 700-1000 ° C.
Ti 2 O 3 is practically insoluble in water. Its hydroxide is formed in the form of a dark brown precipitate when alkalis act on solutions of trivalent titanium salts. It begins to precipitate from acidic solutions at pH = 4, has only basic properties and does not dissolve in excess alkali. However, metal titanites (Li, Na, Mg, Mn) produced from HTiO 2 were obtained dry. Blue-black “titanium bronze” of the composition Na0.2TiO 2 is also known.
Titanium (III) hydroxide is easily oxidized by atmospheric oxygen. If there are no other substances capable of oxidation in the solution, hydrogen peroxide is formed simultaneously with the oxidation of Ti(OH) 3. In the presence of Ca(OH) 2 (binding H 2 O 2), the reaction proceeds according to the equation:
2Ti(OH) 3 + O 2 + 2H 2 O = 2Ti(OH) 4 + H 2 O 2
Nitrate salts Ti(OH) 3 are reduced to ammonia.
Purple TiCl 3 powder can be obtained by passing a mixture of TiCl 4 vapor with excess hydrogen through a tube heated to 650 °C. Heating causes its sublimation (with the partial formation of dimer Ti 2 Cl 6 molecules) and then dismutation according to the scheme:
2TiCl 3 = TiCl 4 + TiCl 2
It is interesting that even under normal conditions, titanium tetrachloride is gradually reduced by metallic copper, forming a black compound of the composition CuTiCl 4 (i.e. CuCl·TiCl 3).
Titanium trichloride is also formed by the action of hydrogen on TiCl 4 at the time of release (Zn + acid). In this case, the colorless solution turns purple, characteristic of Ti 3+ ions, and a crystal hydrate of the composition TiCl 3 ·6H 2 O can be isolated from it. A low-stable green crystal hydrate of the same composition is also known, released from a TiCl 3 solution saturated with HCl. The structure of both forms, as well as similar crystalline hydrates of CrCl 3, correspond to the formulas Cl 3 and Cl 2H 2 O. When standing in an open vessel, the TiCl 3 solution gradually becomes discolored due to the oxidation of Ti 3+ to Ti 4+ by atmospheric oxygen according to the reaction:
4TiCl 3 + O 2 + 2H 2 O = 4TiOCl 2 + 4HCl.
Ti3+ ion is one of the very few reducing agents that quite quickly reduce (in an acidic environment) perchlorates to chlorides. In the presence of platinum, Ti 3+ is oxidized by water (with the release of hydrogen).
Anhydrous Ti 2 (SO 4) 3 is green in color. It is insoluble in water, and its solution in dilute sulfuric acid has the violet color usual for Ti 3+ salts. From trivalent titanium sulfate, complex salts are produced, mainly of the types Me·12H 2 O (where Me is Cs or Rb) and Me (with a variable content of water of crystallization depending on the nature of the cation).
The heat of formation of TiO (mp 1750 °C) is 518 kJ/mol. It is obtained in the form of a golden-yellow compact mass by heating a compressed TiO 2 + Ti mixture in a vacuum to 1700 °C. An interesting way of its formation is the thermal decomposition (in a high vacuum at 1000 °C) of titanyl nitrile. Similar in appearance to metal, dark brown TiS is obtained by calcining TiS 2 in a stream of hydrogen (initially, sulfides of intermediate composition are formed, in particular Ti 2 S 3). TiSe, TiTe and silicide of the composition Ti 2 Si are also known.
All TiG 2 are formed by heating the corresponding TiG 3 halides without air access due to their decomposition according to the following scheme:
2TiG 3 =TiG 4 +TiG 2
At slightly higher temperatures, the TiG 2 halides themselves undergo dismutation according to the scheme: 2TiG 2 = TiG 4 + Ti
Titanium dichloride can also be obtained by reducing TiCl4 with hydrogen at 700 °C. It is highly soluble in water (and alcohol), and with liquid ammonia it gives gray ammonia TiCl 2 4NH 3 . A TiCl 2 solution can be prepared by reducing TiCl 4 with sodium amalgam. As a result of oxidation by atmospheric oxygen, the colorless TiCl 2 solution quickly turns brown, then becomes violet (Ti 3+) and, finally, becomes discolored again (Ti 4+). The black precipitate of Ti(OH) 2 obtained by the action of alkali on a TiCl 2 solution is extremely easily oxidized.