| Melting point | 234-236.5 °C(lit.) | 
                        
                            | Boiling point | 178°C | 
                        
                            | Density | 1.23 | 
                        
                            | vapor pressure | 20 hPa ( 80 °C) | 
                        
                            | FEMA | 2224 | CAFFEINE | 
                        
                            | refractive index | 1.6590 (estimate) | 
                        
                            | Flash point | 178°C | 
                        
                            | storage temp. | 2-8°C | 
                        
                            | solubility | Sparingly soluble in water, freely soluble in boiling water, slightly soluble in ethanol (96 per cent). It dissolves in concentrated solutions of alkali benzoates or salicylates. | 
                        
                            | pka | pKa 0.6 (Uncertain) | 
                        
                            | form | Crystals or Crystalline Powder | 
                        
                            | color | Silky white or white | 
                        
                            | Odor | at 100.00 %. odorless | 
                        
                            | PH | pH (10g/l, 25℃) : 5.5~6.5 | 
                        
                            | Odor Type | odorless | 
                        
                            | Water Solubility | 20 g/L (20 ºC) | 
                        
                            | Sublimation | 178 ºC | 
                        
                            | Merck | 14,1636 | 
                        
                            | BRN | 17705 | 
                        
                            | Stability | Stable. Incompatible with strong acids, strong bases, strong oxidizing agents, iodine, silver salts, tannins. Weakly light sensitive in solution. | 
                        
                            | LogP | -0.07 | 
                        
                            | CAS DataBase Reference | 58-08-2(CAS DataBase Reference) | 
                        
                            | IARC | 3 (Vol. 51) 1991 | 
                        
                            | NIST Chemistry Reference | Caffeine(58-08-2) | 
                        
                            | EPA Substance Registry System | Caffeine (58-08-2) |