Volatile silicic compound

Flame Volatile and Silicate Sodium in Coal. Sodium is rapidly volatilized in the flame when it occurs in a non-silicate compound form, chiefly associated with chlorine in bituminous coals and combined with organic compounds in the lignite and sub-bituminous fuels. The fraction of sodium combined with coal silicates remains largely involatile in the pulverized fuel flame. 

Boron has a great affinity for oxygen and occurs in nature only in boric acid or borates. Borates are composed from clusters of flat trigonal BO3 and tetrahedral BO4 groups. The structural chemistry of borates is as rich and complicated as those of silicates, borides, or boranes. Boron oxide is an essential part of borosilicate glasses such as Pyrex. Boron halides are volatile molecular compounds. They are Lewis acids and react violently with water. The subhalides consist of boron chains or clusters that have terminally bound halogen atoms. They are substitution derivatives of the lower boranes. 

An additional retention problem encountered with dry ashing procedures is that posed by the sequestering action of some materials produced during ignition. The binding of iron by condensed phosphates produced by the action of heat on simple phosphates, or retention of several elements on silicate compounds present in the sample are the best known examples. Nevertheless, many studies in this field often present contradictory observations, illustrating clearly the complexity of the retention problems and the need for an adequate dissolution step. On the other hand, with the exception of arsenic and selenium, these considerations indicate that several losses reported as being due to volatilization were, in reality, due to retention problems. 

The main problem of styrene is high emission, which restricts applications in closed compartments (e.g., naval application). Styrene emission is a health hazard (threshold value of 50 ppm). The need to rednce the volatile organic compound (VOC) is not only expressed in government regulations, but also equally and persuasively by various environmental concerns. The evaporation of styrene can be reduced by the addition of waxes or pyrogenic silicic acid with hydrophilic and hydrophobic end groups. However, such additives may affect the interfacial properties of composites made out of polyester resins. Some styrene-less UPE resin formulations using diacrylate monomers have been reported [71]. However, mostly styrene is used as a reactive diluent in UPE resins. 

Organic tellurium compounds and siliceous materials, ie, rock, ore, or concentrates, are fused with mixtures of sodium carbonate and alkaline oxidants, ie, sodium peroxide, potassium nitrate, or potassium persulfate. For volatile compounds, this fusion is performed in a bomb or a closed-system microwave digestion vessel. An oxidising fusion usually converts tellurium into Te(VI) rather than Te(IV). 

Hydrofluoric acid is used to etch glass by reacting with the silicates in glass to produce a very volatile and thermodynamically stable compound, silicon tetrafluoride, SiF4. For example,... 

Patented proposals have been made to heat sodium chloride with phosphoric acid (A. Delhaye) zinc or lead pyrophosphate (L. J. F. Margueritte) or ferric phosphate (A. R. Arrott). The resulting soluble sodium phosphate is decomposed by boiling with lime to form sodium hydroxide, which, if needed, can be converted into carbonate by a current of carbon dioxide. These methods are quite impracticable. In 1809, J. L. Gay Lussac and L. J. Thenard proposed to make soda by the action of steam on a mixture of sodium chloride and silica If these two compounds are melted together there is very little action, for the salt volatilizes before anything but a superficial combination takes place, and the action of salt in the glazing of pottery is probably made possible by the aq. vapour in the furnace gases. The sodium silicate formed by the joint action of sodium and... 

The microalga genus Phaeocystis has a worldwide distribution and is known to develop massive blooms in polar and temperate waters (Riebesell et al. 1995). Spring blooms of Phaeocystis often follow diatom blooms, after the decline of dissolved silicate (Lancelot et al. 2005 Wassman et al. 2005). This colony-forming alga is an important source of the volatile organic sulphur compound dimethyl sulphide (DMS) and its... 

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