Crystal by sublimation

Many papers fail to describe how the crystals were obtained many of the crystals are donated to crystallographers, and the crystallization details are not obtained or are unavailable. Methyl l-thio-/3-D-xylopy-ranoside was synthesized from D-xylopyranose tetraacetate and methanethiol, and crystallized by sublimation or by evaporation of an ethanol solution.15 The initial structure was obtained by recognizing... 

The formation of crystals by sublimation takes place when the vapor of a substance is condensed as a solid without passing through the liquid... 

Under a nitrogen atmosphere 85 % phosphoric acid is added to the green solution, which changes first to purple subsequently the product precipitates as an orange-red solid. It is separated by filtration, washed with water until the washings are neutral, and dried in vacuo. Any unreacted manganese carbonyl may be removed by sublimation under reduced pressure at room temperature (1 mm./20°C.). The pure compound is then obtained as deep orange-red crystals by sublimation (1 mm./ 60°C.). The yield is 0.3-0.35 g. (64-74%). Anal. Found C, 28.6 H, 0.79 O, 37.7 Mn, 32.1. Calcd. for H Mn,(CO)12 C, 28.60 H, 0.56 O, 38.10 Mn, 32.70. 

Caffeine forms white hexagonal crystals by sublimation. Caffeine has a melting point of 238 Celsius, but the crystals begin to sublime when heated to 178 Celsius. Caffeine is only moderately soluble in water, but more soluble in hot water. The crystals are also moderately soluble in alcohol, acetone, but are much more soluble in methylene chloride, chloroform, and practically insoluble in ether. Caffeine is capable of forming a hydrate, which looses it water of hydration when heated to 80 Celsius. Caffeine is a widely used stimulant, ingested by millions in the form of coffee, tea, ect.,... 

It crystallizes by sublimation in octahedra, and by evaporation of its solution s in ffatteued, right rhombic prisms fuses at 2C5 (509 F.), and boils at about 295 (563 F.) soluble in H O and in alcohol vei7 soluble in hot HCl, the solution gelatinizing on cooling. Its solutions have a disagreeable, acid, styptic taste, and are highly poisonoua... 

Hexakistetrahedral crystals by sublimation, mp 160-190 losed tube). A]so reported as mp ]80-]92°. Sparingly sol water. 

Btcwnish-black, cubic crystals by sublimation in hydro-gin, djs 6,2. mp 1041. Oxidizes upon prolonged exposure to moist air. Practically in sol in water and acids, except m-nic, in which it is sol with decompn. 

Crystals by sublimation in vacuo. Disagreeable odor mp 97-98.5". Oxidizes to cystamine on standing in air. Freely Sol in water, alkaline reaction. LDW in mice (mg/kg) 625 orally 250 i.p. (Klayman) (Srivastava, Field). 

In the context of host-guest chemistry, an apohost is a guest-free solid phase of a host. For example, p-tert-butylcalix[4]arene is a well-known host compound that forms solid-state supramolecular complexes with a wide variety of guests. A guest-free apohost) phase can be crystallized by sublimation under vacuum (Figure 2), but a different apohost phase can be grown by slow cooling of a solution of the host in warm tetradecane. This example demonstrates that an apohost can be polymorphic, and the cautious writer is well advised to refer to an apohost phase rather than the apohost phase. 

Furukawa, K., Tajima, Y., and Suzuki, A. (1995) Method of producing siUcon carbide single crystals by sublimation recrystallization process using a seed crystal. US Patent 5,433,167. 

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