Chlorophyll b

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Chlorophyll b
Structure of β-Chlorophyll
CAS number 519-62-0 N
PubChem 6450186 YesY, 11593175 (from spinach) YesY
ChemSpider 16739843 YesY
UNII 5712ZB110R N
EC-number 208-272-4
Jmol-3D images Image 1
Molecular formula C55H70MgN4O6
Molar mass 907.47 g mol−1
Appearance Green
Odor Odorless
Melting point ~ 125 °C (257 °F; 398 K)[1]
Solubility in water Insoluble[1]
Solubility Very soluble in EtOH, ether, C5H5N
Soluble in MeOH[1]
Absorbance See text
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N (verify) (what is: YesY/N?)
The absorption spectrum of both the chlorophyll a and the chlorophyll b pigments. The use of both together enhances the size of the absorption of light for producing energy.

Chlorophyll b is a form of chlorophyll. Chlorophyll b helps in photosynthesis by absorbing light energy. It is more soluble than chlorophyll a in polar solvents because of its carbonyl group. Its color is yellow, and it primarily absorbs blue light.[2]

In land plants, the light-harvesting antennae around photosystem II contain the majority of chlorophyll b. Hence, in shade-adapted chloroplasts, which have an increased ratio of photosystem II to photosystem I, there is a lower ratio of chlorophyll a to chlorophyll b.[3] This is adaptive, as increasing chlorophyll b increases the range of wavelengths absorbed by the shade chloroplasts.

Structure of chlorophyll b molecule showing the long hydrocarbon tail


  1. ^ a b c Lide, David R., ed. (2009). CRC Handbook of Chemistry and Physics (90th ed.). Boca Raton, Florida: CRC Press. ISBN 978-1-4200-9084-0. 
  2. ^ photosynthesis pigments
  3. ^ Kitajima and Hogan 2003