Wednesday, December 19, 2007

Concept Glossary - Introduction

CG-A

CG-B

CG-C

Coordination compounds

Coordination compounds are a special class of compounds in which the central metal atom is surrounded by ions or molecules beyond their valency.

There are also referred to as coordination complexes or complexes.

Haemoglobin, Chlrophyll, and vitamin B-12 are coordination compounds of iron, magnesium and cobalt respectively.

The interesting thing of coordination compounds is that these are formed from apparently saturated molecules capable of independent existence.

Concept Glossary - D

Diastereomers

Diastereomers are the stereoisomers that are not Enantiomers and have different chemical properties and physical properties.
(Concept of stereoisomerism)

CG - E

Enantiomer

d and l (optical) isomers ar also called enantiomers.
A compound and its enantiomer can be distinguished by their effects on polalirsed light
(Concept of stereoisomerism)


Enantiomerism

Optical isomerism is also called enantiomerism.

CG - F

CG - G

CG - H

CG -I

CG - J

CG - K

CG-L

Tuesday, December 18, 2007

CG - M

Mesocompound

In a mesocompound, half of the molecule is the mirror image of the other half. As a result,one chirality centre will rotate the plane of polarised light in one direction andthe other chirality centre will cancel that direction by rotating the polarised in the other direction by the same amount. Hence the resultant roation is zero and meso compounds do not rotate the plane polarised light.

(Concept of stereoisomerism)

CG-N

CG-O

CG - P

CG-Q

CG-R

Racemic mixture:
A mixture of enantiomers in 1:1 amount is optically inactive due ot external cancellation of optical rotation and is called racemic mixture.
(concept of stereoisomerism)

Radioactivity:
The phenomenon of spontaneous emission of active radiations from certain substances is called radioactivity.

Sunday, December 16, 2007