Binary Oxides, Fluorides and Chlorides

In the f-block the lanthanide elements show quite different behaviour, and oxidation state +3 dominates the binary oxides and fluorides formed 

LaClg TaCl3 WCI3 ReCU 0SCI3 lrCl3 AuClg  

In addition to the maximum values attainable, the variety of oxidation states for which compounds can be isolated is of importance. Among the first-row oxides, scandium in Group 3 and zinc in Group 12 appear in only the group oxidation state. In the second and third row, zirconium 

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The binary oxides, fluorides and chlorides formed by the transition elements... 

The atomic and ionic properties of an element, particularly IE, ionic radius and electronegativity, underly its chemical behaviour and determine the types of compound it can form. The simplest type of compound an element can form is a binary compound, one in which it is combined with only one other element. The transition elements form binary compounds with a wide variety of non-metals, and the stoichiometries of these compounds will depend upon the thermodynamics of the compound-forming process. Binary oxides, fluorides and chlorides of the transition elements reveal the oxidation states available to them and, to some extent, reflect trends in IE values. However, the lEs of the transition elements are by no means the only contributors to the thermodynamics of compound formation. Other factors such as lattice enthalpy and the extent of covalency in bonding are important. In this chapter some examples of binary transition element compounds will be used to reveal the factors which determine the stoichiometry of compounds. 

The stoichiometries of the binary oxides, fluorides and chlorides formed by the transitional elements provide an insight into the range of oxidation states which are chemically accessible for each element. 

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