Explore BrainMass

Stereochemistry, Bonding and Formation

Stereochemistry is the study of the structures and spatial arrangement of atoms within a molecule. Although the study of stereochemistry falls under Organic Chemistry, it actually extends into the entire spectrum of inorganic, biological, environmental and physical chemistry. Its main focus is on stereoisomers and how to differentiate them. Stereoisomers are a sub-group of compounds that have the same molecular formula and sequence of bonded atoms; however they differ in the three dimensional arrangement of atoms.

There are four types of stereoisomers: enantiomers, diastereomers, E-Z isomers and confomers.

  1. Enantiomers are two stereoisomers which are mirror images of each other, and are not super-imposable. Thus, the stereogenic center of each enantiomer will have a different chiral configuration.
  2. Diastereomers are two stereoisomers which are not mirror images of each other. The atoms are arranged very differently in three dimensional space even though it has the same sequence of bonded atoms. This may lead to very different physical and chemical properties between the two diastereomers.
  3. E-Z isomers refer to isomers with a double bond to restrict the movement of substituents. This can then lead to two different configurations. If the high-priority substituents are on the same side of the double bond, then this is the Z-isomer. If the high-priority substituents are on the opposite sides of the double bond, then this is the E-isomer.
  4. Confomers refer to molecules with the same structural formula in a different conformation due to bond rotation.

Thus, understanding the many facets of stereochemistry is extremely important in Organic Chemistry, as different stereoisomers will have different properties.


Title Image Credit: Wikimedia Commons

Categories within Stereochemistry, Bonding and Formation

Lewis Structure

Postings: 17

The Lewis Structure depicts the bonding between individual atoms and molecules through illustrating the presence of valence electron pairs.

Chiral Molecules

Postings: 10

A Chiral Molecule is a type of molecule that is non-superposable over its mirror image.


I need help in this question, the diagrams are attached in the pdf file: 6. Four possible structures are shown below for the complex trans-{ML4(n^2-C2H4)2}. L is a neutral 2 electron sigma only donor. The notation 'n^2-C2H4' means that the ethylene is bonded to the metal such that both carbon atoms are interacting simultaneousl

Solvolysis of benzyl chloride

The solvolysis of benzyl chloride proceeds via a carbocation intermediate and occurs more rapidly than the solvolysis of 2-chloro-norbornane and tertiary butyl chloride. However, primary carbocations are the least stable and most difficult to form so that reactions involving these carbocations are usually slow. The best explan

Congeners and their Properties

Please answer and explain where appropriate The brominated flame retardants consist of 209 congeners with different physical-chemical properties and therefore behave differently in the environment. Congener/ Water Solublity (mol/L)/Log KOA/Log KOW/Human BMF 4, 4'-dibromo / 6.57 x 10-7 / 8.64 / 5.86 / - 2,2',4,4'-tetrabro

Assorted Organic, Bio-Organic Chemistry Problems

Please see the attached file for the complete problems. 1) Label each pair of stereoisomers below as: a) enantiomers b) diastereomers c) identical 2) Convert the following Fischer projections into a tetrahedral representation, and assign R or S stereochemistry to each. 3) The reaction below is an example of: a. nucl

Interpretation and Assignment of IR Spectrum of Caffeine

Would you please provide me with some information regarding the infra-red spectrum of caffeine. Attached I have a labeled spectra of caffeine would you please tell me how I would label it. The lines on my spectra of caffeine are :1650.49;1696.46;1548.42;1485.28;1455.52;1356.19;1237.09;758.34;744.96 all of these numbers are on my

Three 13C and 1H NMR Questions.

The fullly formatted problems are in the attached file. For the compound below, determine how many peaks would be present in the compound's normal 13C decoupled spectrum. Propose structures for compounds that fit the following data: C3H6Br2; 2H quintet at 2.4 ppm J = 6 Hz; 4H triplet at 3.5 ppm J = 6 Hz Draw structures

Reactivity Order of Hydrogen Atoms on Propylbenzene

C6H5(CH2CH2CH3) + (CH3)3COOCl -----> C6H5(CHClCH2CH3) (65%) +C6H5(CH2CHClCH3) (25%) + C6H5(CH2CH2CH2Cl) (10%) 1. Refer to above reaction. When propylbenzene reacts with tert-butylhypochlorite three monochlorinated products are formed in the ratios indicated. Calculate a reactivity order for each type of hydrogen atom in pr

Artifical Sweetners

1. a. What is the name of the chemical used in Sweet 'n Low? Draw the structure. b. Why was a temporary restriction placed on the use of this sweetener? What is the Delaney Amendment? 2. a. What is the chemical name and structure of the sweetener used in Equal and Nutrasweet? b. Read the back of a diet soda can. Who is c

Glucose Isomers in Water

Please help with the following problem. When glucose is placed in water two stereoisomers are formed, one with the new OH on the opposite side of the ring than the 6th carbon, the α (alpha) isomer; and the other with the new OH group on the same side of the ring as the 6th carbon, β (beta) - anomer. Thus, a new chiral car

Liquid crystals

Are there differences between the cholesteryl benzoates and the cholesteryl esters having long carbon chains? why or why not?

Organic Chemistry Questions: stereochemistry and chirality centers

See attached file for full problem description. 1. Write the complete stepwise mechanism for this reaction. Be sure to show all intermediate structures and all electron flow using arrows. 2. Predict the products of the following reaction. Indicate regiochemistry and stereochemistry when relevant.

Resonance structures

Draw all resonance structures possible for the following ionic species: Make sure you clearly show all lone pairs and any formal charges. (See attached file for full problem description)

Drawing Alkane/Alkene Structures

Write the structures of the following compounds a) 2,2-dibromo-3,3-dichloro-5,5-difluoro-6,6-diiodobicyclo{2.2.1}heptane b) hexamethylbicyclo{2.2.0}hexa-2,5-diene


(See attached file for full problem description) Enzyme-catalyzed hydrolysis of a peptide yields mixtures of smaller peptides. Give the structure of the original peptide which yielded these parts following chymotrypsin and trypsin hydrolysis.

Multiple questions on monosaccharides, carbons, and sugars

I need the following questions answered in the next 45 minutes Thanks Sucrose is hydrolyzed to what two monosaccharides? 1. glucose and fructose 2. glucose and galactose 3. galactose and fructose 4. glucose and maltose Question 2 All chiral D-sugars rotate plane-polarized light 1. clo

Organic Chemistry

1. The compound 2-methyl-1,4-pentadiene would be classified as what type of diene? a. conjugated b. isolated c. cumulated d. internal 2. Select the least stable diene listed below: a. 2,3-pentadiene b. trans-1,3-pentadiene c. cis-1,3-pentadiene d. 1,4-pentadiene 3. Whic

Conjugation in Alkadienes & Allylic Systems

What are the differences between vinylic & allylic hydrogens in a Cyclohexene (ie. how many of each, what determines it)? Second, what is the best way to determine a conjugated diene? Are there any rules? In 1,1-dimethylallyl the cation is positive: which type of carbon is that, tertiary? In 1,3-butadiene is the act

Splitting pattern predictions

Help required for predicting the splitting patterns expected for each proton (proton 1 and proton 2) in 2,3-dimethylbutane. What is the number of adjacent hydrogens and what are the splitting patterns?

13C NMR spectral data

I need help with matching the spectral data to the correct structures. Please see attachment.

Stereochemistry of Anthracene and Polycyclic Benzenoid

I need some help with these two questions on stereochemistry, bonding and formation. 1. There are four reasonable resonance structures for anthracene. Draw them. 2. A large number of polycyclic benzenoid aromatic hydrocarbons are known. One of these, benz/a/pyrene, is a powerful carcinogen found in tobacco smoke. From the

Treatment of one stereoisomer of 2-iodo-3-phenylbutane

PROBLEM: Treatment of one stereoisomer of (2 ?, 3R)-2-iodo-3-phenylbutane with base, yields (E)-2-phenylbutene. a) Determine which enantiomer of 2-iodo-3-phenylbutene gives the E product (2R, 3R or 2S, 3R), and explain clearly (using unambiguous diagrams) why that is the case. b) Assign that enantiomer as either R or


Stereoisomers in organic chemistry. See attached file for full problem description.


Please see attached... I chose there are a total of 2 steroisomers and both are optically active

Fischer projections

9. a. Using Fischer projections, draw all the possible stereoisomers 2, 4-dihydroxybutane (CH3-CHOH-CHOH-CH3) b. Label the relationships of your answers in "A" as enantiomers, diastereomers, or Meso ( if any) c. Assign absolute configurations to the chiral carbons n one of your Fischer projections. d. Indicate which of the

Match the structures below with the best description of the type of alkyl halide... See attached Provide structures of products for the following reactions. Include 3-dimensional stereochemistry and absolute configurations where appropriate. If more than one product is possible, circle that which is predominant.

Organic Chemistry - Chlorination of Propane

The chlorination of propane yields 4 different dichloropropanes of formula C3H6Cl2. Using the following information to identify dichloropropanes A,B,C,D. i. If each dichloropropane is further chlorinated to yield trichloropropanes. Compound A gave one trichloropropane, B gave two, C and D each gave three. ii. Dichloropropane D