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Other common desiccants include activated charcoal, calcium sulfate, calcium chloride, and molecular sieves (typically, zeolites). Desiccants may also be categorized by their type, either I, II, III, IV, or V. These types are a function of the shape of the desiccant's moisture sorption isotherm. Alcohols and acetones are also dehydrating agents.
When a visible indication of the moisture content of the silica gel is required, ammonium tetrachlorocobaltate(II) (NH 4) 2 [CoCl 4] or cobalt(II) chloride CoCl 2 is added. [6] This will cause the gel to be blue when dry and pink when hydrated. [6] Due to a link between the cobalt chloride and cancer, it has been forbidden in Europe for use in ...
A vacuum desiccator (left) and desiccator (right). Silica gel with cobalt chloride indicator placed in the lower shelf is used as the desiccant.. A desiccator is a heavy glass or plastic container, now somewhat antiquated, used in practical chemistry for drying or keeping small amounts of materials very dry.
List of desiccants: [1] Activated alumina; Aerogel; Benzophenone (as anion) Bentonite clay; Calcium chloride; Calcium hydride; Calcium oxide; Calcium sulfate (Drierite) Cobalt(II) chloride; Copper(II) sulfate; Lithium chloride; Lithium bromide; Magnesium chloride hexahydrate; Magnesium sulfate; Magnesium perchlorate; Molecular sieve; Phosphorus ...
The desiccant, usually an otherwise-inert solid such as silica gel, fills the space under the platform. Colour changing silica may be used to indicate when it should be refreshed. Indication gels typically change from blue to pink (if the indicator is cobalt(II) chloride) as they absorb moisture but other colours may be used.
Anhydrous cobalt(II) chloride is blue, while the hexahydrate is magenta in colour. [1] Because the color change of cobalt(II) chloride in different hydrates, it can be used to manufacture color-changing silica gel. Anhydrous cobalt halides react with nitric oxide at 70~120 °C to generate [Co(NO) 2 X] 2 (X = Cl, Br or I).
Cobalt(II) chloride is an inorganic compound, a salt of cobalt and chlorine, with the formula CoCl 2.The compound forms several hydrates CoCl 2 ·n H 2 O, for n = 1, 2, 6, and 9. . Claims of the formation of tri- and tetrahydrates have not been confirmed
This first set of criteria governs the choice of the coating ingredient. The coating consists either in a single ingredient or a mix. This mix has different physical forms: solution, emulsion, suspension, powder, etc. It has its own characteristics. In addition, a fluid may be required such as spraying, cooling, heating or drying air.