chloro definition
chloro means product is organochlorine which is harmful;
chloro in chlorophyll means colour and “phyll” means a leaf. It looks green to the human eye but it does not have a green band in the energy level diagram. The leaves appear green every where except when they become old when they look yellow or red. As the cold weather starts, the green leaves change to yellow and red before dropping. One Mg ion is found in the centre of a porphyrin group in the chlorophyll and there is a long phytol chain. The Mg ion uses the light energy to synthesize the molecules. If one of the terminating groups is CH3 it is called a-form and when this CH3 is replaced by CHO, it is called b-form. In the a-form, there are two strong absorption bands one at 430 nm (blue) and the other at about 642 nm (red). In the b- form they are shifted to 453 nm and 642 nm. The fluorescence occurs at 673 nm. The frequencies depend on the method of extraction, in particular, on the solvent used to extract chlorophyll from the leaf.