Studying the properties of iron (III) oxide and hydroxides, obtaining iron (III) hydroxides

Iron(III) hydroxide

- inorganic compound, iron (III) oxide polyhydrate (iron metal hydroxide) with the formula Fe2O3*nH2O, reddish-brown crystals, insoluble in water. The stoichiometric compound Fe(OH)3 has not been isolated.[1] Shows weak amphoteric properties with a predominance of basic ones. When kept under an alkaline solution, it transforms into iron metahydroxide (FeO(OH)).[1]

Chemical properties

• Upon partial dehydration, it decomposes to ferrous acid (or iron metahydroxide):

\mathsf{Fe_2O_3* nH_2O \ \xrightarrow{T}\ FeO(OH) + (n-1)H_2O } (200-250^\circ C)

• Decomposes when heated:

\mathsf{Fe_2O_3*nH_2O \ \xrightarrow{500-700}\ Fe_2O_3 + nH_2O }

• Reacts with acids:

\mathsf{Fe_2O_3 * nH_2O + 6HCl \ \xrightarrow{}\ 2FeCl_3 + (n+3)H_2O }

• and alkalis:

\mathsf{Fe_2O_3 * nH_2O + 3KOH \ \xrightarrow{concentrated}\ Fe_2O_3 (colloid) + (K_3[Fe(OH)_6] impurity) }

Iron salts

• Salts in which iron has an oxidation state of +2 (FeCl2, FeSO4) have reducing properties: iron sulfate FeSO4 is used as fungicides, a wood preservative, and as a component of electrolytes;
• Ferric chloride FeCl2 is used to obtain iron (III) chloride, as a catalyst in organic synthesis.

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Literature

• Chemical Encyclopedia / Editorial Board: Knunyants I.L. and others. - M.: Soviet Encyclopedia, 1990. - T. 2. - 671 p. — ISBN 5-82270-035-5.
• Chemist's Handbook / Editorial Board: Nikolsky B.P. and others. - 2nd ed., rev. - M.-L.: Chemistry, 1966. - T. 1. - 1072 p.
• 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.

Receipt

Iron (II) hydroxide can be obtained in the form of a precipitate in exchange reactions of solutions of iron (II) salts with alkali, for example:

FeSO4 + 2KOH ⟶ Fe(OH)2↓ + K2SO4

The formation of iron (II) hydroxide is one of the stages of iron rusting:

2Fe + 2H2O + O2 ⟶ 2Fe(OH)2 Also, iron (II) hydroxide can be obtained by electrolysis of a solution of alkali metal salts (for example, sodium chloride) with stirring. First, an iron salt is formed, which, when reacted with the resulting sodium hydroxide, gives iron hydroxide. To obtain divalent hydroxide, electrolysis must be carried out at a high current density. General reaction: Fe + 2H2O ⟶ Fe(OH)2↓ + H2

An excerpt characterizing Iron(III) Hydroxide

- Mom, tell me what happened to you in the barn? Pelageya Danilovna smiled. “Oh, well, I forgot…” she said. - You won’t go, will you? - No, I'll go; Pepageya Danilovna, let me in, I’ll go,” said Sonya. - Well, if you're not afraid. - Luiza Ivanovna, may I? – asked Sonya. Whether they were playing ring, string or ruble, or talking, as now, Nikolai did not leave Sonya and looked at her with completely new eyes. It seemed to him that today, only for the first time, thanks to that corky mustache, he fully recognized her. Sonya really was cheerful, lively and beautiful that evening, like Nikolai had never seen her before. “So that’s what she is, and I’m a fool!” he thought, looking at her sparkling eyes and her happy, enthusiastic smile, making dimples on her cheeks from under her mustache, a smile that he had never seen before. “I’m not afraid of anything,” said Sonya. - Can I do it now? - She stood up. They told Sonya where the barn was, how she could stand silently and listen, and they gave her a fur coat. She threw it over her head and looked at Nikolai. “What a beauty this girl is!” he thought. “And what have I been thinking about so far!” Sonya went out into the corridor to go to the barn. Nikolai hurriedly went to the front porch, saying that he was hot. Indeed, the house was stuffy from the crowded people. It was the same motionless cold outside, the same month, only it was even lighter. The light was so strong and there were so many stars on the snow that I didn’t want to look at the sky, and the real stars were invisible. In the sky it was black and boring, on earth it was fun. “I’m a fool, a fool! What have you been waiting for so far? thought Nikolai and, running onto the porch, he walked around the corner of the house along the path that led to the back porch. He knew that Sonya would come here. Halfway along the road there were stacked fathoms of firewood, there was snow on them, and a shadow fell from them; through them and from their sides, intertwining, the shadows of old bare linden trees fell onto the snow and the path. The path led to the barn. The chopped wall of the barn and the roof, covered with snow, as if carved from some kind of precious stone, glittered in the monthly light. A tree cracked in the garden, and again everything was completely silent. The chest seemed to breathe not air, but some kind of eternally youthful strength and joy. Feet clattered on the steps from the girls' porch, there was a loud creaking sound on the last one, which was covered in snow, and the voice of an old girl said: “Straight, straight, along the path, young lady.” Just don't look back. “I’m not afraid,” answered Sonya’s voice, and Sonya’s legs squealed and whistled in her thin shoes along the path towards Nikolai. Sonya walked wrapped in a fur coat. She was already two steps away when she saw him; She also saw him not as she knew him and as she had always been a little afraid. He was in a woman's dress with tangled hair and a happy and new smile for Sonya. Sonya quickly ran up to him. “Completely different, and still the same,” thought Nikolai, looking at her face, all illuminated by moonlight. He put his hands under the fur coat that covered her head, hugged her, pressed her to him and kissed her on the lips, above which there was a mustache and from which there was a smell of burnt cork. Sonya kissed him in the very center of his lips and, extending her small hands, took his cheeks on both sides. “Sonya!... Nicolas!...” they just said. They ran to the barn and returned each from their own porch. When everyone drove back from Pelageya Danilovna, Natasha, who always saw and noticed everything, arranged the accommodation in such a way that Luiza Ivanovna and she sat in the sleigh with Dimmler, and Sonya sat with Nikolai and the girls. Nikolai, no longer overtaking, rode smoothly on the way back, and still peering at Sonya in this strange moonlight, looking for in this ever-changing light, from under his eyebrows and mustache, that former and present Sonya, with whom he had decided never again to be separated. He peered, and when he recognized the same and the other and remembered, hearing that smell of cork, mixed with the feeling of a kiss, he deeply inhaled the frosty air and, looking at the receding earth and the brilliant sky, he felt himself again in a magical kingdom. - Sonya, are you okay? – he asked occasionally. “Yes,” answered Sonya. - And you ? In the middle of the road, Nikolai let the coachman hold the horses, ran up to Natasha’s sleigh for a moment and stood on the lead. “Natasha,” he told her in a whisper in French, “you know, I’ve made up my mind about Sonya.” -Did you tell her? – Natasha asked, suddenly beaming with joy. - Oh, how strange you are with those mustaches and eyebrows, Natasha! Are you glad? – I’m so glad, so glad! I was already angry with you. I didn't tell you, but you treated her badly. This is such a heart, Nicolas. I am so glad! “I can be nasty, but I was ashamed to be the only happy one without Sonya,” Natasha continued. “Now I’m so glad, well, run to her.” - No, wait, oh, how funny you are! - said Nikolai, still peering at her, and in his sister, too, finding something new, extraordinary and charmingly tender, which he had never seen in her before. - Natasha, something magical. A? “Yes,” she answered, “you did great.” “If I had seen her before as she is now,” thought Nikolai, “I would have asked long ago what to do and would have done whatever she ordered, and everything would have been fine.” “So you’re happy, and I did good?” - Oh, so good! I recently quarreled with my mother over this. Mom said she's catching you. How can you say this? I almost got into a fight with my mom. And I will never allow anyone to say or think anything bad about her, because there is only good in her. - So good? - Nikolai said, once again looking for the expression on his sister’s face to find out if it was true, and, squeaking with his boots, he jumped off the slope and ran to his sleigh. The same happy, smiling Circassian, with a mustache and sparkling eyes, looking out from under a sable hood, was sitting there, and this Circassian was Sonya, and this Sonya was probably his future, happy and loving wife. Arriving home and telling their mother about how they spent time with the Melyukovs, the young ladies went home. Having undressed, but without erasing their cork mustaches, they sat for a long time, talking about their happiness. They talked about how they would live married, how their husbands would be friends and how happy they would be. On Natasha’s table there were mirrors that Dunyasha had prepared since the evening. - Just when will all this happen? I'm afraid I never... That would be too good! – Natasha said getting up and going to the mirrors. “Sit down, Natasha, maybe you’ll see him,” said Sonya. Natasha lit the candles and sat down. “I see someone with a mustache,” said Natasha, who saw her face.

Norm of iron in the blood (Fe, Iron)

Every cell needs oxygen to maintain life. Its delivery is carried out by special blood cells, inside of which there is a direct carrier - hemoglobin. The structure of this protein is quite complex; one of the key features is the presence of Fe ions in it, without which the protein completely loses its abilities and cannot perform the function of gas exchange. Thus, the main role of this macroelement is to participate in providing all organs and tissues with oxygen.

Iron, which is located inside red blood cells, is not detected by standard biochemistry. There is also deposited (in the liver, spleen) and extracellular (serum).

Whey is found in plasma and is divided into two fractions - free and protein-bound. The free one is very toxic, so it is quickly removed from the bloodstream either in the direction of disposal or binds to proteins.

Protein-bound is connected to transferrin, and it is this that is taken into account in biochemical analysis. Despite the fact that this fraction is relatively small compared to others, the protein-bound level best reflects macronutrient metabolism.

The activity of cellular respiration depends on many factors: body weight, height, age, physical and mental stress, metabolism. Accordingly, the oxygen demand of the body also changes the need for ferrum. Thus, in children under 1 year of age, the Iron norm is 7.2 – 18.0 µmol/l. For children under 14 years old – from 9.0 to 21.5. In adults, the indicator depends on gender:

Men: 10.7 – 30.4;

Women: 9.0 – 23.3.

The increase is somewhat less common and is associated with:

• Hemolytic anemia (damage to the red blood cell membrane);
• Lack of folic acid, vitamins B6 and B12;
• Genetic pathology of the formed elements of red blood and small intestine;
• Viral, toxic hepatitis, pyelonephritis, glomerulonephritis;
• Overdose of iron-containing drugs.

There is no specific clinical picture of increased ferrum content, but this condition is accompanied by pathologically high hemoglobin against the background of a decrease in the number of red blood cells, impaired skin pigmentation, and pain in the upper abdomen.

A lack of metal in the body is much more common, which indicates:

• Insufficient intake from food (the average person needs 10-15 mg per day);
• Frequent or chronic infections, especially of the gastrointestinal tract, hepato-biliary system;
• Insufficient absorption in the small intestine;
• Cirrhosis, severe hepatosis (the liver is not able to produce carrier proteins);
• Chronic bleeding (stomach ulcer, ulcerative colitis, hemorrhoids, anal fissure);
• Malignant tumors (large, with decay, generalized, systemic, metastatic).

Concentrations may decrease during pregnancy, although this is more a physiological process than a pathology.

Symptoms of reduced content are, first of all, an anemia clinic:

• Weakness;
• Dyspnea;
• Heartbeat;
• Paleness of the skin and mucous membranes;
• Increased fatigue.

In addition, deficiency leads to:

• Pathological changes in the immune system, which manifests itself in frequent infectious diseases;
• Digestion and absorption of many useful substances, including vitamins;
• Deterioration of the health of the skin and mucous membranes (impairment of their barrier function);
• General delay in growth and development;
• Cognitive disorders.

Measuring Fe in a biochemical analysis is mandatory if anemia is suspected (presence of symptoms, changes in other studies). To diagnose other conditions, iron should be determined in combination with additional methods.