Selenium oxide fluorides

The existence of [SeFe] " is doubtful because Sep4 forms only [SeFs] anions with alkali fluorides.The pentachloroselenate ion is present in a hydrochloric acid solution of selenium oxide at 0°C and in solid [Et4N][SeCl5] or [Ph4As][SeCl5]. ... 

The magnetic criterion is particularly valuable because it provides a basis for differentiating sharply between essentially ionic and essentially electron-pair bonds Experimental data have as yet been obtained for only a few of the interesting compounds, but these indicate that oxides and fluorides of most metals are ionic. Electron-pair bonds are formed by most of the transition elements with sulfur, selenium, tellurium, phosphorus, arsenic and antimony, as in the sulfide minerals (pyrite, molybdenite, skutterudite, etc.). The halogens other than fluorine form electron-pair bonds with metals of the palladium and platinum groups and sometimes, but not always, with iron-group metals. 

Chlorine trifluoride Metals Chromium trioxide Alkali metals Dichlorine oxide Oxidisable materials Nitryl fluoride Metals See Selenium, etc., below See also Non-metal oxides, above See also Sulfur, below See also Sulfuric acid, below... 

The platinum metal chalcogenides in general are easier to prepare than the corresponding oxides. Whereas special conditions of temperature and pressure are required to prepare many of the oxides, the platinum metals react most readily with S, Se, and Te. A number of additional differences concerning the chemistry of the chalcogenides and the oxides are summarized as follows The metal—sulfur (selenium, tellurium) bond has considerably more covalent character than the metal-oxygen bond and, therefore, there are important differences in the structure types of the compounds formed. Whereas there may be considerable similarity between oxides and fluorides, the structural chemistry of the sulfides tends to be more closely related to that of the chlorides. The latter compounds... 

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