Magnesium, and Mercury

Calcium, Magnesium, and Mercury.—Complete reduction to benzene results when hexafluorobenzene saturated with water reacts with atomic calcium. Pentafluorophenylmagnesium compounds may be prepared by reaction of ethylmagnesium halide with CjFbX (X = H, Cl, Br, or 1). Both bromines 

Bis-(3-bromotetrafluorophenyl)mercury may form a Grignard compound, since upon reaction with two moles of magnesium in THF followed by hydrolysis it yields (3-HC4F4),Hg (20%). With three moles of magnesium some bromo-l,2,3,5-tetrafluorobenzene was formed after hydrolysis, indicating some Hg-Mg exchange this did not apparently occur with (3-BrC,H4)iHg, and only to a limited extent with (4-BrC H )sHg.  

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Hernandez, H. R., U. Biermacher and A.M. Mattocks Application of the Schwarzenbach method to the analysis of official calcium, magnesium and mercury compounds. Bull. nat. Formulary Comm. 18, 145 (1950). 

In many syntheses activation is not effected by sonochemical preparation of the metal alone but rather by sonication of a mixture of the metal and an organic reagent(s). The first example was published many years ago by Renaud, who reported the beneficial role of sonication in the preparation of organo-lithium, magnesium, and mercury compounds [86]. For many years, these important findings were not followed up but nowadays this approach is very common in sonochemistry. In another early example an ultrasonic probe (25 kHz) was used to accelerate the preparation of radical anions [87]. Unusually for this synthesis of benzoquinoline sodium species (5) the metal was used in the form of a cube attached to the horn and preparation times in diethyl ether were reduced from 48 h (reflux using sodium wire) to 45 min using ultrasound. 

The oigano zme, cadmium, magnesium, and mercury compounds are formed upon the rpe of zinoio chloride (ZaCl,) —... 

Potassium, sodium, magnesium, and mercury can be distilled over niobium without formation of alloys arsenic, antimony, and tellurium do not form alloys below 500° to 600° C. 

OXIDATION OF BORON, SILICON, TIN, MAGNESIUM, AND MERCURY COMPOUNDS... 

Exchange reactions between stable organometallics and palladium salts are useful for preparing isomerically pure organopalladium species to be used in situ for insertion reactions. Exchanges have been made with organocobalt , -iron , -phosphorus , -silicon , -lead , -tin , -boron , -thallium , -zinc , -magnesium and -mercury . Of these, mercurials are most often used, e.g. ... 

Silicon.—Quite a few fluoro-aliphatic derivatives of silicon have been prepared in connection with studies on oigano-lithium, -magnesium, and -mercury compounds... 

Figure 6 is a plot of mean pH and alkalinity values for all streams against time in days. As can be seen from Figure 6, pH and alkalinity changes were closely paralleled during the study period October 3, 1978 to Novamber 16, 1978. A comparison of stream and precipitation magnesium and mercury variations... 

Zinc, magnesium, and mercury have also been used to effect coupling (65, 66). 

Metallic ions may influence the formation of calcium phosphates in different ways. Some inhibit (nickel, tin, cobalt, manganese, copper, zinc, gallium, thalium, molybdenum, cadmium, antimony, magnesium, and mercury), a few stimulate (iron [ferric] and iridium) whereas others have no effect (cerium, titanium, chromium, iron [ferrous], iridium, palladium, platinum, silver, gold, aluminum, and lead) (Okamoto and Hidaka, 1994). Figure 9.14 gives the induction time for calcium phosphate formation vs. concentration for the above metal ions. 

In 1950, Renaud published a generally overlooked paper on the use of ultrasoimd in the preparation of organolithium, -magnesium, and -mercury compounds. For many years, these findings remained unapplied, probably because reliable, cheap generators were not easily available. This situation has changed now and many laboratories possess at least ultrasonic cleaning baths, which permit many synthetic applications (p. 304). 

To determine cyanide and total cyanides (containing both simple and metal-cyanide complexes) in solutions, more drastic conditions are necessary to decompose the complexes before the HCN is distilled off. Several metal-cyanide complexes such as Cd, Cu, Ni, and Zn react almost as readily. But, cyanide complexes of iron show resistance to decompose under the same condition. Cobalt cyanides decompose very slowly. Conversion of metal cyanides to HCN is facilitated by the presence of magnesium and mercury salts. A useful form of distillation was developed by Serf ass et al. [4]. They used magne-sium(ll) and mercury(ll) chlorides with H2SO4 to decompose complex cyanides. These reduced hexacyanoferrate(ll) and hexacyanoferrate(III) to magnesium(II) and mercury(II)... 

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