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Any of a group of green pigments that capture light energy used as the energy source in photosynthesis and that are found in the chloroplasts of plants and other photosynthetic organisms such as cyanobacteria, especially:
a. A waxy blue-black microcrystalline green-plant pigment, C55H72MgN4O5, with a characteristic blue-green alcohol solution. Also called chlorophyll a.
b. A similar green-plant pigment, C55H70MgN4O6, having a brilliant green alcohol solution. Also called chlorophyll b.