Search results
Results From The WOW.Com Content Network
Camphor being purified on a sublimation apparatus. Note the white purified camphor on the cold finger, and the dark-brown crude product. Dark green crystals of nickelocene, freshly sublimed on the cold finger of the sublimation apparatus.
Dark green crystals of nickelocene, sublimed and freshly deposited on a cold finger Sublimation of iodine. Sublimation is the transition of a substance directly from the solid to the gas state, without passing through the liquid state. [1] The verb form of sublimation is sublime, or less preferably, sublimate. [2]
The sublimation sandwich method (also called the sublimation sandwich process and the sublimation sandwich technique) is a kind of physical vapor deposition used for creating man-made crystals. Silicon carbide is the most common crystal grown this way, though other crystals may also be created with it (notably gallium nitride ).
Camphor (/ ˈ k æ m f ər /) is a waxy, colorless solid with a strong aroma. [5] It is classified as a terpenoid and a cyclic ketone.It is found in the wood of the camphor laurel (Cinnamomum camphora), a large evergreen tree found in East Asia; and in the kapur tree (Dryobalanops sp.), a tall timber tree from South East Asia.
Cold finger used in sublimation.The raw product (6) is in the bottom of the outer tube (4) which is heated (7) while under vacuum (through side-arm 3). The sublimated material collects (5) on the cold finger proper, cooled by a coolant (blue) circulated through ports 1 and 2.
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.
For a liquid–gas transition, is the molar latent heat (or molar enthalpy) of vaporization; for a solid–gas transition, is the molar latent heat of sublimation. If the latent heat is known, then knowledge of one point on the coexistence curve , for instance (1 bar, 373 K) for water, determines the rest of the curve.
In crystal growth, a Knudsen cell is an effusion evaporator source for relatively low partial pressure elementary sources (e.g. Ga, Al, Hg, As). Because it is easy to control the temperature of the evaporating material in Knudsen cells, they are commonly used in molecular-beam epitaxy .