Article: Caffeine

This article is about the chemical substance caffeine. For other uses, see Caffeine (disambiguation).

Caffeine
General
Systematic name	1,3,7-trimethyl-1H-purine-2,6(3H,7H)-dione
Other names	1,3,7-trimethylxanthine trimethylxanthine theine mateine guaranine methyltheobromine
Molecular formula	C8H10N4O2
SMILES	O=C1C2=C(N=CN2C)N(C(=O)N1C)C
Molar mass	194.19 g/mol
Appearance	Odorless, white needles or powder
CAS number	[58-08-2]
Properties
Density and phase	1.2 g/cm3, solid
Solubility in water	Slightly soluble
Melting point	237 °C
Boiling point	178 °C (sublimes)
Acidity (pKa)	10.4
Hazards
MSDS	External MSDS
Main hazards	May be fatal if inhaled, swallowed or absorbed through the skin.
NFPA 704	1 2 0
Flash point	N/A
RTECS number	EV6475000
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Caffeine (sometimes called guaranine when found in guarana, mateine when found in mate, and theine when found in tea) is a xanthine alkaloid found in the leaves and beans of the coffee tree, in tea, yerba mate, guarana berries, and in small quantities in cocoa, the kola nut and the Yaupon holly. In plants, caffeine acts as a natural pesticide that paralyzes and kills many insects feeding upon them. The name is derived apparently from Italian caffè ("coffee") plus the alkaloid suffix -ine.

Caffeine is a central nervous system (CNS) stimulant, having the effect of warding off drowsiness and restoring alertness. Beverages containing caffeine — such as coffee, tea, soda and energy drinks — enjoy popularity great enough to make caffeine the world's most popular psychoactive drug.

In nature, caffeine is found with widely varying concentrations of the other xanthine alkaloids theophylline and theobromine, which are cardiac stimulants. When caffeine appears to have different effects depending on the source, it is due primarily to varying concentrations of other stimulants and absorption rates of the mixture.