Preparation of ruthenium tetroxide solution

Preparation of Ruthenium Tetroxide Solution. Ruthenium dioxide (0.4 g) is suspended in 50 ml carbon tetrachloride. A solution of 3.2 g sodium metaperiodate in 50 ml water is added and the mixture stirred 1 hr at 0°. The black ruthenium dioxide gradually dissolves. 

Preparation of Ruthenium Tetroxide (/5) In a 250-ml flask equipped with a magnetic stirrer and cooled in an ice-salt bath is placed a mixture of 0.4 g of ruthenium dioxide and 50 ml of carbon tetrachloride. A solution of 3.2 g of sodium metaperiodate in 50 ml of water is added and the mixture is stirred 1 hour at 0°. The black ruthenium dioxide gradually dissolves. The clear yellow carbon tetrachloride layer is separated and filtered through glass wool to remove insoluble materials. The solution may be used immediately or stored in the cold in the presence of 50 ml of sodium metaperiodate solution (1 g/50 ml). As prepared above, the solution is about 0.037 M in ruthenium tetroxide and contains 0.3 g/50 ml. 

The general method for ruthenium tetroxide staining is to stain sections over a fresh 1% solution for about 5-30 min. This is a problem as ruthenium tetroxide solutions are quite unstable, though Trent et al [166] have frozen solutions in sealed glass containers for periods up to six months and report that ruthenium tetroxide can be prepared by oxidation of hydrated ruthenium dioxide using sodium periodate (available from Morton Thiokol, Inc., Alfa Products). The reaction, shown in the following equation [177] ... 

Ruthenium tetroxide dissolves to a slight extent in water. It is also soluble in caustic alkali, from which solutions a black precipitate of finely divided ruthenium is obtained on addition of alcohol.2 Both the aqueous solution and the pure substance itself possess an odour resembling that of ozone. Its vapour, however, is not poisonous like that of the corresponding tetroxide of osmium. In contact with alcohol the solid tetroxide is reduced with explosive violence.3-4 When covered with water, to which a concentrated solution of caesium chloride is subsequently added and a little hydrochloric acid, ruthenium tetroxide is gradually converted into the oxy-salt, Cs2Ru02CI4. The corresponding rubidium salt has likewise been prepared.3... 

The tetroxides of ruthenium and osmium are solids of low m.p. (RUO4, 25°. OSO4, 41°). R11O4 volatilises when a stream of Clg is passed through an alkaline solution of a ruthenate and is conveniently prepared by oxidising potassium ruthenate with periodic acid (Martin, 1952) ... 

Shaffer et al [365] have continued to modify staining techniques for TEM of latex particles. Recent work on structured latex particles prepared by seeded emulsion polymerization focused on the effects of changes in polymerization variables, such as batch versus semicontinuous, core-shell ratio, shell thickness and shell composition. In this system the core was poly(n-butyl acrylate) and the shell was poly(benzyl methacrylate-styrene). A few drops of the latex was combined with a few drops of a 2% uranyl acetate solution which serves as a negative stain. A drop of that mixture was deposited on a stainless steel formvar-coated grid. After drying it was stained in ruthenium tetroxide vapor to differentiate the rubbery core, which is not... 

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