[Chemistry Class Notes] on Protein Structure Pdf for Exam

You might not know, but protein is the most abundant substance in your body water. Every single cell in your body consists of a protein. Proteins have a unique 3-D structure, enabling it to perform a variety of functions. Protein structures refer to a condensation of amino acids which forms peptide bonds. There are four types of structure in proteins. They are the primary structure of protein, the secondary structure of protein, tertiary, and quaternary. The primary structure is nothing but the sequence of amino acids in the protein. Secondary structure refers to dihedral angles of peptide bonds, and tertiary structure refers to the folding of protein chains. In this article, we have explained the essential protein structure in an easy-to-digest format.

Protein Structure Definition

Proteins are nothing but biological polymers. They are polymers of amino acids joined together by amino acids. You must know that amino acids are the building blocks of proteins. It means that proteins have a chain-like structure, where amino acids are the primary ingredient.  The term structure, when it is used in relation to proteins, goes on to have a much more complex meaning than it generally does for small molecules. Proteins are macromolecules and it has four different levels of structure – i.e. primary, secondary, tertiary and quaternary.

 

These amino acids get linked together with peptide bonds. When such a few bonds get linked together, it becomes a polypeptide chain. When one or more of these polypeptide chains get twisted or folded, it forms a protein.  

 

The size of the protein varies significantly. It is dependent on the number of polypeptide molecules it holds. Insulin is one of the smallest protein molecules out there. Titin is the largest protein molecule, having 34,350 amino acids.  

 

Classification of protein: Fibrous and globular are two types of proteins, decided by their molecular shape. When polypeptide chains run parallel, bonded by hydrogen and disulfide, you get a fiber-like structure. And when chains coil around, they give out a spherical shape.  

 

Also, four types of structure make up a protein molecule. You can learn about them below. The image below can help you with understanding protein structures. 

 

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Primary Protein Structure 

The primary structure of a protein refers to a unique formation and sequence in which amino acids get combined. They all get linked together to produce a protein molecule. The primary structure is responsible for giving particular properties to protein. Depending on the side-chain substituent, an amino acid can be classified into being acidic, basic or neutral. Although twenty amino acids are required for the synthesis of various proteins found in humans, we can synthesize only ten. The remaining ten are called essential amino acids and must be obtained in a diet.

 

The amino acid sequence of a protein is kind of encoded in the DNA. Proteins are synthesized by a series of steps called transcription and translation. Often, post-translational modifications, such as glycosylation or phosphorylation which occur are necessary for the biological function of the protein. While the amino acid sequence makes up the primary structure of the protein, the chemical and biological properties of the protein are very much dependent on the three-dimensional or tertiary structure.

 

In total, there are 20 amino acids in the human body. They all have two groups – carboxyl and amino group. However, each one has a variable group, called an ‘R’ group. That R group is accountable for lending a unique structure to a protein. 

 

All the protein gets determined by the sequencing of the amino acids. This formation and sequence of amino acids in proteins is exceptionally unique. If you change even a single amino acid in the chain, then you can end up with a non-functioning protein.

Secondary Protein Structure 

This secondary protein structure gives a unique shape to the protein. It’s where the peptide backbone of a protein structure gets folded onto itself. The folding of the polypeptide chains occurs because of the interaction between the carboxyl group and amine groups of the peptide chains. 

 

Secondary protein structure gives out two types of shapes; they are α-helix and β-pleated sheets.

  • α-helix – The backbone of protein follows a helical structure. Across different layers of the helix, the hydrogen forms bonds with oxygen, rendering a helical structure.  The side-chain substituents of the amino acid groups in an α helix extend to the outside. Hydrogen bonds form between the oxygen of each C = O bond in the strand. The hydrogen of each N – H group four amino acids below it in the helix. The hydrogen bonds make this structure very much more stable. The side-chain substituents of the amino acids always fit in beside those N-H groups. 

  • β-pleated sheet – In this shape, polypeptide chains get stacked next to each other. The external hydrogen molecules of these chains form intramolecular bonds, giving it a sheet-like structure. The hydrogen bonding occurs between strands, rather than within strands. The sheet conformation consists of pairs of strands that are lying side by side.  The carbonyl oxygen in one strand bonds with the amino hydrogen of the adjacent strand. The two strands can either be parallel or antiparallel depending on whether the strand directions are the same or opposite. The antiparallel ß-sheet is more stable due to the more well-aligned hydrogen bonds. 

Tertiary Protein Structure 

Tertiary structure is responsible for the formation and 3-D shape of the protein. As amino acids form bonds during secondary structure, they give out shapes such as helices and sheets. Further, the structure can coil or fold randomly, and that’s what you call the tertiary structure of proteins. When the structure gets disturbed, the protein becomes denatured. Such a protein gets chemically affected, and the structure becomes distorted. The protein molecule will bend and twist in such a way so as to achieve the maximum stability or lowest energy state. The three-dimensional shape of a protein may seem to be irregular and random. It is fashioned by many stabilizing forces due to the bonding interactions between the side chain groups of the amino acids.

Quaternary Protein Structure 

The spatial arrangement of two or more peptide chains leads you to a quaternary protein structure. You should know that proteins don’t necessarily need to have a quaternary structure. Also note that primary, secondary, and tertiary structures of proteins are available in all-natural proteins. But, that’s not the case for quaternary structure. Thus, when a particular protein has the first three structures, it can qualify to be a protein. 

Analysis of Protein Structure

The complexities of a protein structure do make the elucidation process of a complete protein structure extremely difficult, even with the most advanced analytical equipment.  An amino acid analyzer can be used to determine which amino acids are present and their molar ratios. The sequence of the protein can then be analyzed by means of peptide mapping, and the use of Edman degradation. This process is routine for peptides and small proteins but more complex for large multimeric proteins. 

One method which is used to characterize the secondary structure of a protein is called circular dichroism spectroscopy. The different types of secondary structure, α-helix, ß-sheet, and random coil, all have characteristic circular dichroism spectra in the far-UV region of the spectrum. To determine the three-dimensional structure of a protein by X-ray diffraction, a large and well-ordered single crystal is required. X-ray diffraction allows the measurement of the short distance between atoms and it yields a three-dimensional electron density map, which can be used to build a model of the protein structure.  

The use of NMR to determine the three-dimensional structure of a protein has some advantages over X-ray diffraction. It can be carried out in solution form, and thus the protein is free from the constraints of the crystal lattice. The two dimensional NMR techniques generally used are NOESY which measures the distance between atoms through space, and COESY which measures distance through bonds. The variety of methods for determining protein stability emphasizes the complexity of the nature of protein structure and the importance of maintaining that structure for a successful pharmaceutical product. 

[Chemistry Class Notes] on Quinoline Pdf for Exam

Quinoline is a heterocyclic organic compound. The chemical name of quinoline is alpha, beta benzopyridine. The molecular formula for quinoline is C9H7N. In the quinoline molecular formula, then C represents the carbon, H represents the hydrogen and the numbers written in subscript represent the number of respective elements. Quinoline is found in coal tar and bore oil.

 

Structure of Quinoline

Quinoline consists of a benzene ring fused to the alpha-beta-position of the pyridine ring. In the quinoline structure, there are five double bonds present and eleven single bonds are present. The single bonds are sigma bonds formed by the head-on overlapping. The double bond consists of one sigma bond and one pi bond. The pi bonds are formed by the lateral overlapping of the p orbitals.

 

Preparation Methods of Quinoline

1. Skraup Synthesis Method: 

This method is the most widely used method for the preparation of quinoline. In this method, aniline and glycerol are heated at a high temperature in the presence of sulphuric acid and mild oxidising agents like nitrobenzene or the presence of peroxides like arsenic peroxide. Ferrous sulphate (FeSO4) or boric acid (H3BO3) is generally added to make the reaction less violent because skraup synthesis is a highly exothermic reaction. 

 

Mechanism of Skraup Synthesis Method:

Step 1: In this step, glycerol undergoes a dehydration reaction in the presence of sulphuric acid to give acrolein. 

 

Step 2: In this step, the above-formed acrolein reacts with the aniline and forms an intermediate as a product of this reaction. 

 

Step 3: In this method the cyclization of the intermediate takes place. This cyclization process occurs in the presence of concentrated sulphuric acid to form 1, 2-dihydro quinoline.

 

Step 4: In this step, the oxidation of 1,2-dihydroquinoline takes place on the reaction with nitrobenzene. On reacting with nitrobenzene, 1,2-dihydroquinoline forms the quinoline as a product.

 

2. Friedlander Synthesis- 

In this method, ortho- amino benzaldehyde is condensed with acetaldehyde in the presence of sodium hydroxide (NaOH) solution by the cyclisation process. 

 

3. Doebner- 

Miller Synthesis- Primary aryl amines with free ortho positions can react with the alpha, beta-unsaturated carbonyl compound in the presence of acid to yield quinolines.

 

4. Knorr Quinoline Synthesis- 

In this reaction, the condensation of aniline takes place with the beta- ketoester at a high temperature to give an anilide intermediate. This formed anilide intermediate undergoes the cyclisation process. The concentrated sulphuric acid is added to the reaction for the dehydration process. The dehydration phenomena lead to the production of 2-hydroxyquinolines.

 

Properties of Quinoline

Physical Properties of Quinoline

  • Quinoline is a colourless liquid chemical.

  • The boiling point of the quinoline is 237 degrees celsius.

  • Quinoline is composed of a large number of hydrophobic carbon chains that makes it sparingly soluble in water.

  • Quinoline is soluble in organic solvents. 

  • The nature of quinoline is basic due to the presence of the pyridine ring. In the pyridine ring, the lone pair is present on the nitrogen atom. Therefore, it can donate a lone pair of electrons, hence, basic.

 

Chemical Properties of Quinoline

Quinoline gives an electrophilic substitution reaction due to the presence of resonance phenomena in the molecule. 

  • Quinoline gives a nitration reaction in the presence of concentrated nitric acid and concentrated sulphuric acid.

  • Quinoline gives a bromination reaction in the presence of bromine and silver sulphate. 

  • Quinoline compound reacts with the potassium permanganate and undergoes the oxidation reaction. In the oxidation process quinoline gets converted into nicotinic acid.

  • Quinoline undergoes a reduction reaction in the presence of tin and hydrochloric acid and gets converted into decahydroquinoline.

Two Important derivatives of Quinoline

1. Quinoline yellow: Quinoline yellow is a quinoline derivative. It’s used to add colour to stuff. Quinoline yellow is a beta-diketone and aromatic ketone that belongs to the quinoline family. Quinoline has the molecular formula C18H11NO2. Quinoline’s chemical name is quinophthalone. Quinoline has a molecular weight of 273.3 g/mol. 

2. Amino Quinoline: Amino quinoline is a derivative of quinoline. The amino group takes the place of the hydrogen in the eighth spot. As a consequence, it’s also known as quinoline’s eight amino derivative. Amino quinoline has a structure that is identical to 8-hydroxyquinoline. 

SAR of Quinolines

SAR of quinolines stands for the similar structure-activity relationship of quinolines. The study of quinolines is necessary for the comparison of the antimalarial activity. The asymmetry at the third carbon and fourth carbon is not necessary for the antimalarial activity. The substitution of the halogen group at eight carbon positions will increase the antimalarial activity of the drug. The presence of a methoxy group is not necessary for the antimalarial activity.

 

Quinoline Uses

  • Quinoline is an aromatic compound, used mainly for the production of intermediate compounds in the manufacture of other products.

  • It is used in agriculture for the raising and farming of animals and growing of crops.

  • It is used as an agrochemical.

  • Its materials are used in the building process, such as flooring, insulation, caulk, tile, wood, glass, etc.

  • It is used as chemicals in cigarettes, or tobacco-related products, or related to the manufacturing of tobacco products.

 

Did You Know?

  • Quinoline is also known as quinoline yellow lake, due to its yellow colour. It is an aluminium salt of quinoline. 

  • The alkaloids of quinoline can be derived from rutaceous plants.

  • Quinoline is slightly basic.

Conclusion

This is all about Quinoline, its structure, properties, and uses. Learn how this chemical compound is synthesised and used in different processes. Focus on how the synthesis processes differ from each other by considering the steps of the reactions. 

[Chemistry Class Notes] on Reactions of Alcohols Pdf for Exam

Alcohols are organic molecule that contain one or more hydroxyl groups attached to the aliphatic or aromatic carbon group with the covalent Bond. The compounds obtained by replacing one hydrogen atom from aliphatic hydrocarbons by hydroxyl group are alcohols whereas those obtained by replacing the hydrogen atom of aromatic hydrocarbons are phenols. 

In this article, we have discussed the various alcohol reactions. 

Methods of Formation of Alcohol

The important methods of formation of alcohols are given below:

1. Preparation From Haloalkanes- Haloalkanes, when boiled with aqueous NaOH or KOH or moist silver oxide (AgOH), give alcohols. General reaction for the preparation of alcohols by this method is given below:

R-X + KOH (aq) → R-OH + KX

C2H5Br + KOH  → C2H5-OH + KBr

Primary haloalkanes give a good yield of alcohol. However, tertiary haloalkanes in this reaction give mainly alkenes due to dehydrohalogenation. Secondary haloalkanes give a mixture of alcohol and alkenes.

2. By Reduction of Aldehydes and Ketones- alcohols can be prepared by the reduction of aldehyde and ketones. The reduction is carried by common reducing agents such as hydrogen in the presence of a catalyst (platinum, palladium, and nickel), sodium in the presence of the alcohol, and lithium aluminium hydride.

Chemical Reaction of Alcohol 

In alcohols reactions, alcohol can act both as nucleophiles as well as electrophiles. Alcohols behave as nucleophiles in the reactions in which the bond between O-H is broken. Alcohols can behave as electrophiles in the reactions in which the bond between C-O is broken.

1. Oxidation of Alcohols- The oxidation of alcohols involves the formation of carbon-oxygen double bond (C=O) with cleavage of O-H and C-H bonds. This type of cleavage and formation of bonds occur in oxidation reactions. These reactions are also called dehydrogenation reactions because they involve the loss of hydrogen from alcohol. 

  1. Oxidation of primary alcohols- A primary alcohol is easily oxidised to form first an aldehyde and then a carboxylic acid. Both the aldehyde and the acid formed to contain the same number of carbon atoms as the parent alcohol.

  2. Oxidation of Secondary Alcohols- A secondary alcohol is easily oxidised to form a ketone with chromic anhydride. The ketone may be further oxidised under strong conditions to form a mixture of acids. While the ketone contains the same number of carbon atoms as the parent alcohol, the acids formed, contain a lesser number of carbon atoms.

  3. Oxidation of Tertiary Alcohol- The oxidation of tertiary alcohol is very difficult because it does not have hydrogen in the carbon-bearing hydroxyl group (OH). However, the oxidation of tertiary alcohol can be possible when treated with acidic oxidising agents under very strong conditions at elevated temperatures, cleavage of various C-C bonds takes place. They form mixtures of ketones and carboxylic acids. Both the ketones and acids contain a lesser number4 of carbon atoms than the starting alcohols. 

2. Reduction of Alcohol- The Reduction of alcohol is not an easy step. The hydroxyl group (OH) is a poor leaving group. Therefore, the direct reduction of alcohol is not possible at normal room temperature and pressure. The alcohol can be first converted into any other compound by an oxidation reaction and then it can be reduced to the alkane form. Only indirect methods of reduction of alcohols are possible.

3. Acidic Reaction of Alcohol- Alcohols are weakly acidic in nature. Therefore, it reacts with active metals such as sodium, potassium, magnesium, aluminium, etc. to liberate hydrogen gas and form metal alkoxide.

Ethanol Reaction

Ethanol is lower alcohol that gives all the general acidic reactions. Therefore, it is called ethanol acid.

Reaction with Active Metal

C2H5OH + 2M → C2H5OM + H2

Reaction with Metal Hydrides

C2H5OH + NaH → C2H5O- Na + H2

Reaction with Carboxylic Acid

C2H5OH + ROH → RCOOC2H5

4. Dehydration Reaction of Alcohols- The most common question asked by the student in organic chemistry is primary alcohols undergo what reaction to form alkenes? The answer to this question is the dehydration reaction. When the alcohols are heated with a protonic acid such as conc.H2SO4 or H3PO4 at 443 K, they get dehydrated to form alkenes. This reaction mechanism involves three steps:

  • Protonation of alcohol mechanism

  • Elimination of Water molecule (dehydration)

  • Elimination of hydrogen ion (deprotonation)

5. Hydrolysis of Alcohol

The hydrolysis reaction of alcohol is a kind of oxidation reaction. In this reaction, the water molecule acts as a catalyst. Aldehydes and ketones are formed as the main products in this hydrolysis reaction.

CH3CH2OH + H2O → CH3CHO + H2O + H2

Did You Know?

  • Biological oxidation of methanol and ethanol occurs in the body.

  • If an alcoholic person, by mistake, drinks denatured alcohol the methanol is oxidised in the body first to methanal and then to methanoic acid, which can cause blindness and death.

[Chemistry Class Notes] on Reformatsky Reaction Pdf for Exam

What is the Reformatsky Reaction?

The name Reformatsky reaction is kept in the honour of a Russian chemist named Sergey Nikolaevich Reformatsky, who discovered this reaction in 1887. This is a reaction that takes place between a carbonyl compound and an alpha‐half ester, which can be an aldehyde, an ester, or a ketone. This reaction takes place mostly in the presence of zinc. This represents the extended reactions between the carbonyl compounds either with an alkyl zinc halide or a dialkylzinc.

Advantage of Reformatsky Reaction Process

An advantage of this reaction is that the organozinc compound isolation is not required. At the time of the reaction process, a new carbon‐carbon linkage can be created along with an organozinc halide formation and the decomposition because of the presence of dilute acids.

Generally, the Reformatsky reaction yields are improved if the reaction is carried out in 2 steps.

  • Firstly, the alpha Bromo ester can be converted into an organozinc bromide

  • By reaction with the zinc compound in pure and dry dimethoxyethane.

This derivative is formed apparently almost in the quantitative yield.

Reformatsky Reaction Definition

According to the general definition, the Reformatsky reaction can be described as an organic reaction used to convert an aldehyde or ketone and α-haloester to a β-hydroxy ester with the help of acid workup and metallic zinc. Here, an inert solvent such as THF (tetrahydrofuran) or diethyl ether is often used as a reaction solvent.

The carbonyl compound’s condensation reaction, along with the alpha haloester in the presence of zinc metal, is referred to as the Reformatsky reaction.

The solvent that is most often used in this reaction is given as ether or benzene or a benzene ether mixture.

Structure of the Reagent

The THF’s complexes crystal structures of Reformatsky reagents ethyl bromozincacetate and tert-butyl bromozincacetate have been determined. These both form cyclic 8-membered dimers in the solid-state but vary in stereochemistry. The 8-membered ring in the ethyl derivative adopts a conformation of tub-shaped and contains cis THF ligands and cis Bromo groups. Whereas, in the derivative of tert-butyl, the ring exists in a chair form and the THF ligands and Bromo groups are the trans.

Reformatsky Mechanism

Let us look at how the reaction takes place and what happens while the reaction occurs.

  • Generally, the Reformatsky reaction commences either with the oxidative insertion or zinc addition into the carbon-halogen bond of an α-haloester.

  • The primary purpose of using zinc is to allow the enolate generation even without using the Bronsted base, which generally condenses either with the aldehyde or ketone itself.

  • After the insertion happens, the compounds get coordinated with each other leading to a dimer formation. Also, this compound further experiences a rearrangement that results in the emergence of 2 zinc enolates.

  • After that, the oxygen of the aldehyde or ketone coordinates to the zinc, and a new rearrangement takes place where the 2 reagents now contain a carbon-carbon bond between them.

  • Following that, an acid workup splits the oxygen bond and zinc to generate β-hydroxy ester and zinc(II) salt as the final products.

On an important note, the α-hydroxy esters product are the essential substances that are required for natural product synthesis and in the pharmaceutical industry.

Identifying the First-order Reaction

First-order reactions are when the reaction rate at any provided time is directly proportional to the reactant’s concentration left at that specific time or the active mass.

The rate law is expressed as R=K[A] 

Let us look at some typical ways to identify it:

  • These types of reactions take forever to get completed finally.

  • The reaction rate decreases exponentially as the time slows down.

  • The sample half-life is simply a constant value. After each half-life, the reactant amount gets halved.

  • The half-life and rate constant are inversely proportional, and none of which depends on the sample’s initial concentration.

  • A graph between the time and logarithm of the concentration of the reactant left forms a straight line.

Advantages of Reformatsky Reaction

A few of the significant advantages of this reaction can be listed as follows:

  • The reformatsky reaction is conducted using highly hindered ketones. This reaction also facilitates the successful addition of nucleophiles to the ketone’s delta positive carbon atom.

  • Reformatsky mechanism can be adapted easily for the intramolecular aldol reactions.

  • The organozinc halide reagents, which are used in the Reformatsky Reaction, are considered relatively stable and are also available commercially.

  • Reformatsky reaction results in the beta-hydroxy ester’s isolation.

  • Another merit of the Reformatsky reaction can be given as the convenience since the reaction is an alternative to the reaction of a ketone or an aldehyde with the preferred lithium enolate of an ester.

  • The yields of Reformatsky were improved with freshly prepared zinc powder, a heated column of zinc dust, acid-washed zinc, trimethylchlorosilane, and copper-zinc couple.

[Chemistry Class Notes] on Rosenmund Reduction Mechanism Pdf for Exam

Rosenmund Reduction Reaction 

In Rosenmund Reaction, acyl chloride is hydrogenated to get reduced into aldehyde and palladium-barium sulphate is used as catalyst. It is a reduction reaction involves addition of hydrogen. 

Rosenmund Reaction can be written as follows –

(Image to be added soon)

Acyl Chloride                                                                                      Alkyl Aldehyde 

R can be an alkyl or aryl group in the above reaction. 

Examples of Rosenmund Reduction Reaction – 

(Image to be added soon)

(Image to be added soon)


Rosenmund Catalyst 

As we have discussed above, Palladium on barium sulphate is called rosenmund catalyst. Use of palladium induces the reduction process while use of barium sulphate reduces the activity of palladium as barium sulphate has low surface area, thus prevents the over reduction. Over reduction should be stopped for the desired product which is aldehyde in this reaction. If over reduction takes place, then aldehyde converts into alcohol which would the react with remaining acyl chloride and form ester. To prevent further hydrogenation, catalyst is mixed with poison. 

Rosenmund catalyst is prepared by reduction of palladium (II) chloride solution in the presence of barium sulphate. 

Rosenmund Reduction Reaction Mechanism 

1. Preparation of Acyl Chloride From an Acid –

(Image to be added soon) SOCl2 or PCl3or PCl5    (Image to be added soon)

Carboxylic Acid                Acyl Chloride 

2. Preparation of Aldehyde – 

We use a poisoned rosenmund catalyst to get the desired product which is aldehyde. So, we use palladium with barium sulphate. 

(Image to be added soon)         Pd-BaSO4 (partial hydrogenation)        (Image to be added soon) + HCl   

If we don’t use poisoned palladium then reaction will take place as follows – 

(Image to be added soon) Pd(non poisoned catalyst)  (Image to be added soon)        Pd  (Image to be added soon)                                                                                                          (Image to be added soon)

In this condition we get ester in place of aldehyde. 

Applications of Rosenmund Reduction Reaction          

1.Rosenmund reduction reaction is used for the production of aldehydes.     

2. It is used for the production of saturated fatty aldehydes. 

3. It is used for the production of alkyl or aryl aldehydes. 

Limitation of Rosenmund Reaction 

We can prepare many aldehydes by Rosenmund Reduction Reactions but formaldehydes cannot be prepared. As formyl chloride is unstable at room temperature. 

Rosenmund reduction reaction is one of the important name reactions of CBSE Class 12 Chemistry for your final board examinations. You need to practice twice all the name reactions to score high marks in the examination. We at have provided “Important Chemical Reactions of Class 12 Chemistry” page also for you so that you can score maximum. You can also find similar articles on other name reactions such as diazotization reaction, hofmann elimination reaction, Friedel crafts reaction etc. at .              

[Chemistry Class Notes] on Samarium Pdf for Exam

What is Samarium?

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To explain what Samarium is, it is a chemical element which is represented by the symbol of the Sm element in the periodic table and the atomic number of Samarium is 62. In the year 1879, Samarium was discovered by Paul Emile Lecoq de Boisbaudran. It is a silvery, hard type of metal which oxidizes slowly in the air. It is a member of the lanthanide series which makes Samarium assuming oxidation state +3. Monoxide SmO, monochalcogenides Sms, SmSe and SmTe and samarium(II) iodide are generally compounds of Samarium. There is no significant biological role which can be found in Samarium, but only Samarium is slightly a toxic element. 

Uses Of Samarium 

What is Samarium used for can be explained as:

  • Samarium-Cobalt magnets which have a very high permanent magnetization is one of the most critical applications of Samarium. These magnets can be seen used in headphones, small motors and musical instruments like guitars.

  • In the manufacturing of solar-powered electric aircraft, this element can be seen.

  • In the making of special infrared absorbing glass and cores of carbon arc lamp electrodes, are considered as uses of Samarium.

  • It also acts as a catalyst in the ethanol dehydration process as well as uses of Samarium can be making new permanent magnets.

Properties Of Samarium 

Physical Properties Of Samarium 

Samarium is a rare earth metal having a hardness and thickness like those of zinc. With a boiling point of 1794 °C, Samarium is the third most volatile lanthanide after ytterbium and europium; this property encourages detachment of Samarium from the mineral ore. At surrounding conditions, Samarium typically accepts a rhombohedral structure (α form). After warming to 731 °C, its crystal symmetry changes into hexagonally close-packed (hcp), anyway the progress temperature relies upon the metal immaculateness. Further warming to 922 °C changes the metal into a body-centred cubic (bcc) stage. Warming to 300 °C joined with pressure to 40 kbar brings about a twofold hexagonally close-packed structure (dhcp). Samarium electron configuration is [Xe] 4f66s2. and Samarium atomic mass is 150.36 u.

Chemical Properties Of Samarium 

Newly prepared Samarium has a silvery radiance. In the air, it gradually oxidized at room temperature and suddenly ignites at 150 °C. In any point, when put away under mineral oil, samarium bit by bit oxidizes and builds up a greyish-yellow powder of the oxide-hydroxide blend at the surface. The metallic appearance of an example can be safeguarded via fixing it under inert gas, for example, argon. 

Samarium is very electropositive and responds gradually with cold water and rapidly with hot water to shape samarium hydroxide: 

2Sm(OH)3 (aq) + 3H2 (g) → 2Sm (s) + 6H2O (l) 

Samarium disintegrates promptly in dilute sulfuric acid to shape solutions containing the yellow to light green Sm(III) ions, which exist as [Sm(OH2)9]3+ complexes: 

2Sm (s) + 3 H2SO4 (aq) → 2 Sm3+ (aq) + 3 S(aq) + 3 H2 (g) 

One of the few lanthanides is samarium that exhibit the +2 oxidation state. The Sm2+ particles are dark red in fluid solution.

Compounds Of Samarium 

Oxides

Sesquioxide Sm2O3 is the most stable oxide of the Sm element. It exists in several crystalline phases, as many other samarium compounds. The trigonal form is obtained by slow cooling of the melt. 

Chalcogenides

Sm element forms trivalent sulfide, telluride and selenide. Divalent Chalcogenides SmS, SmSe and SmTe with cubic rock salt crustal structure are also known. By converting from semiconducting to metallic state at room temperature upon application of pressure is what Chalcogenides of the Sm element are known for.

Halides

Sm element reacts with all the halogens, forming trihalides.

2 Sm (s) + 3 X2 (g) → 2 SmX3 (s) (X = F, Cl, Br or I)

The further reduction with Samarium, lithium or sodium metals at elevated temperatures (about 700–900 °C) yields dihalides. The reduction also produces numerous non-stoichiometric samarium halides with crystal structure adding with the dihalides, such as Sm3F7, Sm14F33, Sm27F64, Sm11Br24, Sm5Br11 and Sm6Br13.

Solved Examples 

  1. About 1016 years is taken for just half the samarium-149 in nature to decay by alpha-particle emission. Explain the decay equation and isotope that is produced by the reaction?

For samarium-149, the atomic number of Samarium is equal to 62 and a mass number is equal to 149. This means 

149=b+4→ mass number conservation

62=a+2→ change conservation

You will get

b=149−4=145

a=62−2=60

The element that has an atomic number equal to 60 is neodymium, Nd.

Neodymium-145 will be produced by the alpha decay of samarium-149 and an alpha particle.

62149Sm —> 60145Nd + 24He

Fun Fact 

  1. Uses of Samarium have no biological role, and it is not that toxic. It is observed that some soluble salts are mildly toxic but cannot affect the human life.

  2. Samarium is said to be the hardest member of the cerium group of earth metals.

  3. Samarium has a bright silver metallic lustre. 

  4. The origin of the name of Samarium is from smarskite, which is a mineral.