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In this video we make triboluminescent or smash-glow crystals. Triboluminescence is the phenomena where light is generated when something is rubbed or fractured. The exact mechanism by which triboluminescence works is still under investigation, but the best theories so far propose that the breaking of the structure causes charge separation that release energy upon recombination. This energy is picked up by nearby atoms, in this case europium, and released as light according to their ionization or fluorescence spectra. Many substances exhibit triboluminescence including sugar and tape. But Europium Tetrakis (Dibenzoylmethide)Triethylammonium is one of the strongest available and its glow can easily be captured by a camera. It's made by mixing 100mL of Ethanol, 2.93g of dibenzoylmethane, 1.4g of europium nitrate pentahydrate and 1.9mL of triethylamine. The mixture is heated until everything dissolves and then allowed to cool slowly to obtain crystals that are filtered off and washed with ethanol. After thorough drying they are ready for use. A frequently asked question is if this stuff is hot when it is used. The answer is no, the crystals do not undergo a chemical transformation and thus they do not release or consume heat, but remain at constant temperature. There may be some small heating due to friction when they are broken, but that is not from the crystals or a special property of triboluminescence.

Triboluminescence Europium dibenzoylmethane tetrakis triethylammonium synthesis science chemistry nature awesome experiment glow in the dark

Grazie mille a Francesca e Lida per le preziose informazioni che mi hanno dato! Ecco qua i nomi dei filtri chimici e fisici che possiamo trovare nelle creme in commercio non solo in Europa ma anche nel resto del mondo: p-Aminobenzoic acid PABA 15% (5% EC-will be banned from sale to consumers from 8 October 2009) EC, USA, AUS Protects against skin tumors in mice.[51][52][53] Shown to increase DNA defects, however, and is now less commonly used. Padimate O OD-PABA, octyldimethyl-PABA, σ-PABA 8% (EC,USA,AUS) 10% (JP) (Not currently supported in EU and may be delisted) EC, USA, AUS, JP Not tested Phenylbenzimidazole sulfonic acid Ensulizole, Eusolex 232, PBSA, Parsol HS 4% (US,AUS) 8% (EC) 3% (JP) EC,USA, AUS, JP Genotoxic in bacteria[54] Cinoxate 2-Ethoxyethyl p-methoxycinnamate 3% (US) 6% (AUS) USA, AUS Not tested Dioxybenzone Benzophenone-8 3% USA, AUS Not tested Oxybenzone Benzophenone-3, Eusolex 4360, Escalol 567 6% (US) 10% (AUS,EU) 5% (JP) EC, USA, AUS, JP Not tested Homosalate Homomethyl salicylate, HMS 10% (EC, JP) 15% (US,AUS) EC, USA, AUS, JP Not tested Menthyl anthranilate Meradimate 5% USA, AUS Not tested Octocrylene Eusolex OCR, 2-cyano-3,3diphenyl acrylic acid, 2-ethylhexylester 10% EC,USA, AUS, JP Increases ROS[7] Octyl methoxycinnamate Octinoxate, EMC, OMC, Ethylmethoxycinnamate, Escalol 557, 2-ethylhexyl-paramethoxycinnamate, Parsol MCX 7.5% (US) 10% (EC,AUS)20% (JP) EC,USA, AUS, JP Octyl salicylate Octisalate, 2-Ethylhexyl salicylate, Escalol 587, 5% (EC <b>...</b>

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Animation of stepwise mechanism of haloform reaction.

organic chemistry reaction mechanism mechanisms carbon