Boron arsenic anions

Sowinski and Suffet 297) have used GC/MS to detect boron hydrides at trace levels, whereas Blum and Richter (298) have used capillary columns in the combined GC/MS of a series of phenylboronate derivatives. There have also been recent applications of GC/MS to the TMS derivatives of inorganic anions (299). The TMS derivatives of ammonium arsenates. 

Compounds with higher aggregated anions, in which the anion-forming element occurs at least twice, are termed isopoly compounds. Usually it is the alkali or ammonium salts of the isopolyacids that are S3mthesized. Compounds with isopolyanions are formed, among others, by boron, silicon, phosphorus, arsenic, sulfur, vanadium, molybdenum and tungsten. They may be prepared in a number of ways, e.g., by fusion of an acid anhydride with an alkali hydroxide, dehydration of acid salts, or treatment of a normal salt with its acid anhydride. 

In covalent hydrides, hydrogen and the metal are linked by a covalent bond. Aluminum, silicon, germaninm, arsenic, and tin are some of the metals whose covalent hydride structures have been stndied extensively. Some ionic hydrides, snch as LiH or MgH2, exhibit partial covalent character. The complex hydrides, such as lithium aluminum hydride and sodium borohydride, contain two different metal atoms, usually an alkali metal cation bound to a complex hydrido anion. The general formula for these compounds is M(M H4) , where the tetrahedral M H4 contains a group IIIA metal such as boron. 

In addition to iodonium, sulfonium and selenonium compounds, onium salts of bromine, chlorine, arsenic, and phosphoras are also stable and can act as sources of cation radicals as well as Bronsted acids, when irradiated with light. Performance of diaryl chloronium and diaryl bromonium salts was studied by Nickers and Abu. Also, aryl ammonium and aryl phosphonium, and an alkyl aryl sulfonium salt were investigated. It appears that the general behavior of these materials is similar to diphenyl iodonium and triphenyl sulfonium salts. These are formations of singlet and triplet states followed by cleavages of the carbon-onium atom bonds and in-cage and out of cage-escape reactivity. The anions of choice appear to be boron tetrafluoride, phosphorus hexafluoride, arsenic hexafluoride, and antimony hexafluoride. 

By far the most serious interference effects in the determination of calcium are due to anions such as phosphate, sulphate, arsenate and oxalate, and to elements such as aluminium, beryllium, boron, chromium, iron and molybdenum which can exist as anions in the flame. These all give rise to reductions in line intensities, probably due to the formation of compounds which are either of low volatility or are not dissociated. 

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