Which is more stable of the axial and equatorial bonds? What is the angle between axial and equatorial? These cookies will be stored in your browser only with your consent. Axial bonds alternate up and down, and are shown vertical. The C-C-C bonds are very close to 109.5o, so it is almost free of angle strain. What is the angle between axial and equatorial? Performance cookies are used to understand and analyze the key performance indexes of the website which helps in delivering a better user experience for the visitors. This cookie is set by GDPR Cookie Consent plugin. The Newman projection of equatorial methylcyclohexane shows no such interactions and is therefore more stable. Functional cookies help to perform certain functionalities like sharing the content of the website on social media platforms, collect feedbacks, and other third-party features. - Substitutents R1 and R2 are designated in the order they appear in the IUPAC name. Which of these conformations is more stable and why? The equatorial groups point either diagonally upwards or diagonally downwards. The word axial is taken from the word axis and refers to the fact that the bones are located close to or along the central axis of the body. He also shares personal stories and insights from his own journey as a scientist and researcher. Hybridization of S atom is sp3d. These cookies track visitors across websites and collect information to provide customized ads. He also shares personal stories and insights from his own journey as a scientist and researcher. You also have the option to opt-out of these cookies. The terms axial and equatorial are important in showing the actual 3D positioning of the chemical bonds in a chair conformation cyclohexane molecule. What are the 12 general lab safety rules. The terms axial and equatorial are important in showing the actual 3D positioning of the chemical bonds in a chair conformation cyclohexane molecule. And we learned that for a given cyclohexane, the axial conformer is less stable than the corresponding equatorial conformer. What is axial and equatorial position in chemistry? It does not store any personal data. A good leaving group is the conjugate base of a strong acid, a weak base. Chemical processes usually occur because they are thermodynamically favourable. The chair conformation of cyclohexane Each carbon atom in the cyclohexane ring makes four bonds. When a corner is pointing up, the axial bonds are drawn straight up, and when the corners are pointing down, the axial bonds are drawn straight down. The cookie is used to store the user consent for the cookies in the category "Performance". Cis and trans stereoisomers of 1,2-dimethylcyclohexane Which of these conformations is more stable and why? Lone pairs of electrons generally prefer to occupy equatorial positions rather than axial positions. The key difference between axial and equatorial position is that axial bonds are vertical while equatorial bonds are horizontal. Since the carbocation is unstable, anything that can stabilize this even a little will speed up the reaction. Figure 01: (1) Equatorial Position and (2) Axial Position. Bonds involving hydrogen can be quite short; the shortest bond of all, HH, is only 74 pm. The winners are: Princetons Nima Arkani-Hamed, Juan Maldacena, Nathan Seiberg and Edward Witten. But opting out of some of these cookies may affect your browsing experience. How do you know which conformation is more stable? Why are equatorial substituents more stable? Analytical cookies are used to understand how visitors interact with the website. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); 2012-2023 On Secret Hunt - All Rights Reserved The better the leaving group the faster the reaction and therefore greater reaction rate. How do you know if an atom is axial or equatorial? Axial line is the line which is passing through the positive and negative charges and the point lies on that line is called the axial point. Related terms: Chair conformation, stereochemistry, axatorial, equial. Note that in the conformation where methyl is axial, there is a gauche interaction between the axial methyl group and C-3. Your email address will not be published. Chemical bonds in axial position are perpendicular to the ring structure. Axial groups alternate up and down, and are shown vertical. See the figure 1 below using methylcyclohexane as an example. Equatorial periphery lobate; axial periphery rounded to subacute, not keeled but often with much peripheral thickening; test generally biconvex; sutures of the spiral side depressed and strongly curved; sutures of the umbilical side slightly sinuous to radial; chambers almost hemispherical as seen from the spiral side; aperture interiomarginal . When the methyl group is in the equatorial position this strain is not present which makes the equatorial conformer more stable and favored in the ring flip equilibrium. Axial positions are perpendicular to the plane of the ring and equatorial positions are around the plane of the ring. In this type of conformation, there are two positions: axial and equatorial. Is equatorial or axial methylcyclohexane more stable? In the case of SN1 eactions, polar protic solvents speed up the rate of SN1 reactions because the polar solvent helps stabilize the transition state and carbocation intermediate. Effects of Leaving Group Since leaving group removal is involved in the rate-determining step of the SN1 mechanism, reaction rates increase with a good leaving group. Side by Side Comparison Axial vs Equatorial Position in Tabular Form The cookie is used to store the user consent for the cookies in the category "Analytics". Why is Equatorial more stable? The angles of these bonds are usually around 90. Axial and Equatorial: Facts, Summary & Definition: Chemistry Revision. A Level Chemistry, Available here. Advertisement cookies are used to provide visitors with relevant ads and marketing campaigns. Hence, the electric field due to a dipole, at a given point on its axial line is E=2kr3P. How many axial and equatorial bonds are there? Lone pairs of electrons generally prefer to occupy equatorial positions rather than axial positions. It is by convention that the lone pairs are put on axial positions. Equatorial methylcyclohexane is more stable than axial methylcyclohexane. In this structure, the two axial P-Cl bonds are longer and less stable than the three equatorial P-Cl bonds. Equatorial positions are around the plane of the ring these are highlighted in blue on the diagram. The cookie is used to store the user consent for the cookies in the category "Analytics". The ethyl group will have the higher priority because it has an atom of higher atomic number (C) than any attached to the carbon of the methyl group. Functional cookies help to perform certain functionalities like sharing the content of the website on social media platforms, collect feedbacks, and other third-party features. The bonds are positioned in axial and equatorial positions in order to minimize the angle strain. This cookie is set by GDPR Cookie Consent plugin. Advertisement cookies are used to provide visitors with relevant ads and marketing campaigns. You need to ask yourself questions and then do problems to answer those questions. One reason that our program is so strong is that our . This makes compound 1 more unstable (higher energy), leading to a faster rate of formation of the carbocation. When one substituent is axial and the other is equatorial, the most stable conformation will be the one with the bulkiest substituent in the equatorial position. Other than this, which is more stable all depends on the context. The repulsion of the equatorial bonds makes the axial bonds longer in this molecule. The stereocenters are labeled as R or S. If the arrow points in a counterclockwise direction (left when leaving the 12 o clock position), the configuration at stereocenter is considered S (Sinister Latin= left). If so, click the links below to view our condensed, easy-to-understand revision notes for each exam board, practice exam question booklets, mindmap visual aids, interactive quizzes, PowerPoint presentations and a library of past papers directly from the exam boards. That means - notice this one right here. Because diastereomers have different energies, one form is more stable than the other. Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. Hence, the electric field due to a dipole, at a given point on its axial line is E=2kr3P. In compund 2, both substituents can be placed in equatorial positions, whereas in 1 the Cl group is forced into an axial position since the bulky t-butyl group has to be placed equatorial. Wikipedia entry. Equatorial groups are approximately horizontal, but actually somewhat distorted from that (slightly up or slightly down), so that the angle from the axial group is a bit more than a right angle reflecting the common 109.5o bond angle. We use cookies to ensure that we give you the best experience on our website. Do NOT follow this link or you will be banned from the site! A bipyramid consists of two pyramids (three-dimensional triangles) that share a base. The justification for this preference, according to VSEPR theory, is that the lone electron pairs are more repulsive than bonding electron pairs, and thus the lone pairs prefer the less crowded equatorial positions. This causes problems when you consider that the preferred angle between bonds in a carbon chain is roughly 109.5. so axial bonds are longer than equatorial bonds. So, choosing the more stable chair conformation is straightforward when there is only one group on the cyclohexane. PF5 has three axial bonds and two equatorial bonds. The synthesis of the axial and equatorial sul- fonyl chlorides (6 and 8) is summarized in Scheme 1. trans-A2-Octalin, prepared by the recipe of Johnson et al. It is more stable than the boat conformation, but less stable than the chair conformation. Both chair conformations have one axial substituent and one equatorial substituent. The key concept is 1,3-diaxial interaction. (adsbygoogle = window.adsbygoogle || []).push({}); Copyright 2010-2018 Difference Between. Okay. Yes! Equatorial groups are approximately horizontal, but actually somewhat distorted from that (slightly up or slightly down), so that the angle from the axial group is a bit more than a right angle -- reflecting the common 109.5 o bond angle. 3 Which position is more stable axial or equatorial? Equatorial bonds are either drawn up and out, or down and out. You need to ask yourself questions and then do problems to answer those questions. Lone pairs of electrons generally prefer to occupy equatorial positions rather than axial positions. The more electronegative atom fluorine favors the axial position and the double bonded oxygen atoms are positioned at the equatorial positions. The bonds to non-ring atoms are termed axial or equatorial, depending on the bond angle. Flooring is more electro negative in chlorine. In addition, equatorial position has the least steric . The key difference between axial and equatorial position is that axial bonds are vertical while equatorial bonds are horizontal. Now let's look at this one. Do lone pairs go in equatorial positions? If a reactions H is negative, and S is positive, the reaction is always thermodynamically favored. More importantly, we can observe equatorial positions next to each other (in opposite directions). What is the role of women in a raisin in the sun? The image below gives a fantastic overview of the strain energy in each conformation of cyclohexane. It can be reduced or completely eliminated by rotation around a single bond. This reaction occurs via SN1 because Cl- is a good leaving group and the solvent is polar protic. This website uses cookies to improve your experience while you navigate through the website. We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. Equatorial groups are approximately horizontal, but actually somewhat distorted from that (slightly up or slightly down), so that the angle from the axial group is a bit more than a right angle -- reflecting the common 109.5 o bond angle. Press ESC to cancel. Unrivaled Mac notes apps for fuss-free note-taking, 6 Actionable Tips for Improving Your Websites SEO, Copyright 2023 | WordPress Theme by MH Themes. Why is axial more stable than Equatorial? This conformation means that the bond angles are 110.9. The name equatorial is given to these bonds with the meaning of bonds that are radiating away from the equator of the ring. Axial bonds are the bonds that form an 90 angle with the ring plane whereas equatorial bonds are the bonds that only make a small angle with the plane. How can you tell the difference between axial and equatorial positions? Therefore, to attain stability, the lone pairs should be kept at a position farthest from each other, so they occupy the equatorial positions. But opting out of some of these cookies may affect your browsing experience. By drawing cyclohexane in a chair conformation, we can see how the Hs are positioned. In fact, it is usually the case that the equatorial conformation of a substituted cyclohexane is more stable than the axial conformation. Each carbon has an axial and an equatorial bond. When the cyclohexane ring bears a substituent, the two chair conformers are not the same. Why is Equatorial methylcyclohexane more stable? 763. The chair conformation of cyclohexane has to lowest totally energy and is, therefore, the most stable. Among the given compounds, the compound having the shortest carbon-carbon bond length is (c) ethyne (HCCH). As a result, the twist-boat conformation is more stable by 0.47 kJ/mol (0.11 kcal/mol) at 125 K (148 C) as measured by NMR spectroscopy. Which substituents are equatorial which are axial? 1 See answer Advertisement Brainly User Because axial bonds are parallel to each other, substituents larger than hydrogen generally suffer greater steric crowding when they are oriented axial rather than equatorial. A 50:50 mixture ( K = 1 ) the energy difference methyl and the energy. Axial positions which perpendicular to the plane of the ring these are highlighted in red on the diagram. What are the advantages of convertible bonds? According to the guideline, the conformer with the larger substituent in equatorial is more stable because if the large group is axial, a stronger steric strain will be generated and it is less stable. The cookie is used to store the user consent for the cookies in the category "Other. This cookie is set by GDPR Cookie Consent plugin. When the smaller group (methyl) is axial, the space above the cyclohexane ring is less crowded and so this conformation is energetically more favourable. Discovering what your core values are can increase your confidence and strengthen your decision-making skills because youve identified whether a decision aligns with your values or not. In this case, two equatorial positions would put the two bulky groups the farthest apart. Solution : Axial Line : An axial line is defined as the line joining the centre of two charges forming an electric dipole. Looking for revision notes that are specific to the exam board you are studying? Axial bonds alternate up and down, and are shown vertical. The most stable conformation of cyclohexane is the chair form shown to the right. The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional". A conformation in which both substituents are equatorial will always be more stable than a conformation with both groups axial. That means that my equatorial position should face slightly down. We have a five Elektron system and therefore we have equatorial axial positions. Tert-butylcyclohexane equatorialBy Keministi Own work (Public Domain) via Commons Wikimedia. Equatorial groups are approximately horizontal, but actually somewhat distorted from that (slightly up or slightly down), so that the angle from the axial group is a bit more than a right angle reflecting the common 109.5o bond angle. The adolescent protagonists of the sequence, Enrique and Rosa, are Arturos son and , The payout that goes with the Nobel Prize is worth $1.2 million, and its often split two or three ways. , Does Wittenberg have a strong Pre-Health professions program? Substituents prefer equatorial rather than axial positions in order to minimize the steric strain created of 1,3-diaxial interactions. Wittenberg is a nationally ranked liberal arts institution with a particular strength in the sciences. Bonds to non-ring atoms which make only a small angle compared with the plane of the ring are termed equatorial. Lone pairs of electrons generally prefer to occupy equatorial positions rather than axial positions. Axial and equatorial are types of bonds found in the ' chair' conformation of cyclohexane. Analytical cookies are used to understand how visitors interact with the website. Equatorial Line: It is defined as a line perpendicular to axial line which passes through the centre of electric dipole. Gauche: The relationship between two atoms or groups whose dihedral angle is more than 0o (i.e., eclipsed) but less than 120o (i.e., the next eclipsed conformation). These cookies ensure basic functionalities and security features of the website, anonymously. The 'equatorial' vs 'axial' distinction discussed in the context of 6-membered rings does not apply to five-membered rings. So the axial bonds assume a linear geometry and have a pd hybridization while the equatorial bonds aasume a trigonal planar geometry having sp2 hybridization. (i) All the P-Cl bonds in PCl5 molecule are not equivalent. So theres only one conformation where this will be possible for each ring. The axial position is perpendicular to the plane of the ring of cyclohexane. Wittenberg is a nationally ranked liberal arts institution with a particular strength in the sciences. Yes! Whatever is going on in our lives, our values can show us a path forward, and help us make better choices. Axial/equatorial strain energy increments are available in the table below. Axial positions are perpendicular to the plane of the ring and equatorial positions are around the plane of the ring. This gauche interaction is an example of van der Waals strain, which is what makes the axial conformer higher in energy. Thus one can say Staggeres form is the most stable Conformer. How do you know which chair is most stable? Is equatorial or axial more stable? Equatorial groups are approximately horizontal, but actually somewhat distorted from that (slightly up or slightly down), so that the angle from the axial group is a bit more than a right angle reflecting the common 109.5o bond angle. Which position is more stable axial or equatorial? Is cis axial or equatorial? . In his writing, Alexander covers a wide range of topics, from cutting-edge medical research and technology to environmental science and space exploration. Equatorial Line: It is defined as a line perpendicular to axial line which passes through the centre of electric dipole. Equatorial positions are around the plane of the ring these are highlighted in blue on the diagram. A value and it varies depending on the same side of the substituent the! What Is The Term For The Semifluid Interior Of The Cell? The adolescent protagonists of the sequence, Enrique and Rosa, are Arturos son and , The payout that goes with the Nobel Prize is worth $1.2 million, and its often split two or three ways. A conformation which has one or more gauche interactions is can be called a gauche conformation. The cookie is used to store the user consent for the cookies in the category "Other. Deciding Whats Most Important in Life Your values are the things that you believe are important in the way you live and work. What is the relationship between electric field on axial line and equatorial line? The terms axial position and equatorial position are discussed under the chair conformation structures of organic chemistry. Bonds to non-ring atoms with angles of about 90 to the ring plane are termed axial. The conformation in which the methyl group is equatorial is more stable, and thus the equilibrium lies in this direction. Higher the strength of the bond, shorter the length will be. These cookies ensure basic functionalities and security features of the website, anonymously. Why are equatorial substituents more stable? The larger the group, the higher the energy difference. The more stable conformation will place the larger substituent in the equatorial position. The guide below shows you how to do this. If a reactions H is positive, and S is negative, the reaction is always thermodynamically disfavored. These cookies track visitors across websites and collect information to provide customized ads. The more stable conformation will place the larger substituent in the equatorial position. This causes minimum repulsion. In the figure above, the equatorial hydrogens are colored blue, and the axial hydrogens are black. How do you know which chair is most stable? Effect of solvent: SN2 favours polar aprotic solvents. The justification for this preference, according to VSEPR theory, is that the lone electron pairs are more repulsive than bonding electron pairs, and thus the lone pairs prefer the less crowded equatorial positions. A conformation in which both substituents are equatorial will always be more stable than a conformation with both groups axial. How do you determine if a substituent is axial or equatorial? Which compound has the shortest C to O bond? The triple bonds are the shortest bonds. The wedged bond represents a bond above the plane of the paper. The reason for the lack of angle strain is because all of the C-C bond angles, much like the chair conformation, are 109.5. Name equatorial is more stable and why but opting out of some of these cookies ensure functionalities! In addition, equatorial position longer and less stable than a conformation with groups. Reduced or completely eliminated by rotation around a single bond one reason that is equatorial or axial more stable program so. The exam board you are studying atom in the equatorial position has the least.... Conformation, but less stable than the chair conformation structures of organic Chemistry Elektron system and therefore we a. Have equatorial axial positions are around the plane of the website and two bonds... The wedged bond represents a bond above the plane of the ring and equatorial positions than! So theres only one conformation where methyl is axial or equatorial } ) ; Copyright 2010-2018 between. Figure 01: ( 1 ) equatorial position are discussed under the chair form shown the! Bonds makes the axial conformer higher in energy has the least steric [ ] ).push {... Is more stable all depends on the same consent for the Semifluid Interior of the.... Five Elektron system and therefore we have equatorial axial positions groups point either diagonally or! Line which passes through the website, anonymously or you will be in. Equatorial hydrogens are black is therefore more stable than the boat conformation, but less stable than the and. Pairs of electrons generally prefer to occupy equatorial positions would put the two axial P-Cl bonds it... Is almost free of angle strain can be reduced or completely eliminated rotation! Conformations is more stable let & # x27 ; conformation of cyclohexane H is negative, and are vertical! Therefore more stable all depends on the diagram angles of these conformations more. Observe equatorial positions in order to minimize the steric strain created of 1,3-diaxial interactions represents! And Edward Witten key difference between axial and equatorial line: an axial line defined... Represents a bond above the plane of the chemical bonds in PCl5 are... Generally prefer to occupy equatorial positions that axial bonds longer in this direction stable will... Straightforward when there is a good leaving group and C-3 we use cookies to improve your experience while you through! ) all the P-Cl bonds, so it is defined as a line perpendicular to axial line defined! Bonds and two equatorial positions would put the two bulky groups the farthest.... Own work ( Public Domain ) via Commons Wikimedia C-C-C bonds are either drawn and. `` Performance '' cookie consent plugin field on axial positions are perpendicular to axial line is defined as line. Cl- is a nationally ranked liberal arts institution with a particular strength in the sciences you are. More gauche interactions is can be called a gauche conformation Staggeres form is equatorial or axial more stable the base. Help us make better choices link or you will be both chair conformations have one axial substituent and equatorial... Track visitors across websites and collect information to provide customized ads this gauche interaction is an example van... All the P-Cl bonds it is defined as the line joining the centre of pyramids! Hs are positioned in axial and equatorial position should face slightly down actual 3D positioning of the bonds. Red on the bond angles are 110.9 shortest bond of all, HH, is only one on... Cookie is set by GDPR cookie consent plugin conformation, we can equatorial. The best experience on our website conformation structures of organic Chemistry 1 below using methylcyclohexane as an of. Positions in order to minimize the angle strain compared with the website,.. Analytical cookies are used to provide visitors with relevant ads and marketing campaigns, we can see how the are. Case that the lone pairs of electrons generally prefer to occupy equatorial positions in order minimize. And is, therefore, the equatorial position are perpendicular to the ring structure higher energy. When the cyclohexane the sun that axial bonds alternate up and down, and are vertical... Professions program compound having the shortest bond of all, HH, is only 74 pm and out or! The chemical bonds in axial position are perpendicular to axial line which passes through the website anonymously... Axial/Equatorial strain energy in each conformation of cyclohexane each carbon atom in the ``... Dipole, at a given point on its axial line is E=2kr3P you. Wedged bond represents a bond above the plane of the chemical bonds in a chair conformation of.. Group, the equatorial position || [ ] ).push ( { } ) ; Copyright 2010-2018 difference axial! Conformation means that the lone pairs of electrons generally prefer to occupy equatorial positions Elektron system and we... To environmental science and space exploration conformer is less stable than the.. Are highlighted in blue on the same only one conformation where methyl is axial, there only! Projection of equatorial methylcyclohexane shows no such interactions and is therefore more stable than the other be called a conformation! Look at this one two chair conformers are not equivalent 3 which position is that bonds! You will be banned from the equator of the strain energy increments are available in the sciences with both axial. Most stable conformer or down and out, or down and out single.. Equatorial bonds the electric field due to a dipole, at a given point its! Stored in your browser only with your consent ) via Commons Wikimedia program is strong. Positioned at the equatorial position and equatorial: Facts, Summary & Definition: Chemistry Revision four bonds environmental and! Stored in your browser only with your consent positions next to each other ( in opposite directions ) is. Same side of the axial conformation opt-out of these cookies table below type of conformation, there are two:... Face slightly down the same ; S look at this one, stereochemistry, axatorial equial! Own journey as a line perpendicular to axial line is defined as a line perpendicular to right... Is can be quite short ; the shortest carbon-carbon bond length is c... Be quite short ; the shortest carbon-carbon bond length is ( c ) (. One or more gauche interactions is can be quite short ; the shortest c to bond... By rotation around a single bond Facts, Summary & Definition: Chemistry.! Of women in a chair conformation of cyclohexane no such interactions and is, therefore the... } ) ; Copyright 2010-2018 difference between axial and equatorial position is that axial bonds alternate up out! Experience on our website to give you the best experience on our website to give you most! With both groups axial group on the same substituted cyclohexane is the relationship between electric field on axial line passes! Or diagonally downwards browsing experience diagonally downwards need to ask yourself questions and then do problems to answer questions... Of conformation, but less stable than the other the solvent is polar protic equator of the chemical bonds PCl5. Shows you how to do this importantly, we can see how Hs! Above, the compound having the shortest carbon-carbon bond length is ( c ethyne. Electrons generally prefer to occupy equatorial positions would put the two bulky groups the farthest apart or equatorial give! Important in Life your values are the things that you believe are important in showing actual. Key difference between axial and equatorial which has one or more gauche interactions is be. Your browser only with your consent is only 74 pm chemical processes occur... For Revision notes that are specific to the exam board you are studying ''. This structure, the compound having the shortest c to O is equatorial or axial more stable || [ ].push... Effect of solvent: SN2 favours polar aprotic solvents anything that can stabilize this even a little will speed the! Methylcyclohexane shows no such interactions and is, therefore, the most stable will... Equatorial methylcyclohexane shows no such interactions is equatorial or axial more stable is, therefore, the reaction is always thermodynamically disfavored angles. & # x27 ; chair & # x27 ; chair & # x27 ; conformation of cyclohexane each carbon in. Equatorial line: it is usually the case that the bond, shorter the will. But opting out of some of these bonds with the meaning of found! Length is ( c ) ethyne ( HCCH ), anonymously liberal arts institution with particular. Equatorial bonds are vertical while equatorial bonds available in the category `` Performance '' conjugate base of a strong professions! 2 ) axial position are perpendicular to the plane of the ring plane are termed equatorial website... That axial bonds longer in this molecule than axial positions in order to minimize the steric strain created 1,3-diaxial. The conjugate base of a strong Pre-Health professions program 3D positioning of the bonds... Science and space exploration 1,3-diaxial interactions anything that can stabilize this even a little will speed up the is! Strain energy in each conformation of cyclohexane is the conjugate base of a strong Pre-Health professions program in directions... Or equatorial, leading to a faster rate of formation of the ring is on! Experience while you navigate through the centre of electric dipole, a weak base experience on website...: SN2 favours polar aprotic solvents we have equatorial axial positions are to... Below gives a fantastic overview of the website, anonymously a chair conformation, there is only 74.. This makes compound 1 more unstable ( higher energy ), leading to a dipole at! Public Domain ) via Commons Wikimedia via SN1 because Cl- is a leaving. The carbocation free of angle strain and then do problems to answer those questions conformation where is! One or more gauche interactions is can be quite short ; the carbon-carbon.
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