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Sublimation is caused by the absorption of heat which provides enough energy for some molecules to overcome the attractive forces of their neighbors and escape into the vapor phase. Since the process requires additional energy, sublimation is an endothermic change.
In thermodynamics, the enthalpy of sublimation, or heat of sublimation, is the heat required to sublimate (change from solid to gas) one mole of a substance at a given combination of temperature and pressure, usually standard temperature and pressure (STP). It is equal to the cohesive energy of the solid.
They observed that while the endo isomer is formed more rapidly, longer reaction times, as well as relatively elevated temperatures, result in higher exo / endo ratios which had to be considered in the light of the remarkable stability of the exo-compound on the one hand and the very facile dissociation of the endo isomer on the other.
The term was later also applied to the indirect sublimation transfer printing process, which uses a standard ink-jet printer to deposit sublimation-capable ink onto a transfer sheet. The printed transfer sheet is then pressed with the substrate with heat, transferring the dye to the substrate, such as plastic or fabric, via sublimation.
The opposite of an endothermic process is an exothermic process, one that releases or "gives out" energy, usually in the form of heat and sometimes as electrical energy. [1] Thus, endo in endothermic refers to energy or heat going in, and exo in exothermic refers to energy or heat going out. In each term (endothermic and exothermic) the prefix ...
Endo and exo transition states for cyclopentadiene adding to acrolein; endo/exo product ratio for this and various other dienophiles. Diels–Alder reactions in which adjacent stereocenters are generated at the two ends of the newly formed single bonds imply two different possible stereochemical outcomes.
into exo and endo ring closures, depending whether the bond broken during the ring closure is inside (endo) or outside (exo) the ring that is being formed; into tet, trig and dig geometry of the atom being attacked, depending on whether this electrophilic carbon is tetrahedral (sp 3 hybridised), trigonal (sp 2 hybridised) or diagonal (sp ...
Closed space sublimation is a method of producing thin-films, esp. cadmium telluride photovoltaics, though it is used for other materials like antimony triselenide. [1] Diagram showing working principle of CSS. It is a type of physical vapor deposition where the substrate to be coated and the source material are held close to one another. They ...