Compounds with oxoanions

Because of the high ratio of ionic charge to radius, normal salts of Ti cannot be 

The anhydrous nitrates can be prepared by the action of N2O5 on MCI4. Ti(N03)4 is a white sublimable and highly reactive compound (mp 58°C) in which the bidentate nitrate ions are disposed tetrahedrally around the titanium which thereby attains a coordination number of 8 (Fig. 21.4). Infrared evidence suggests that Zr(N03)4 is isostmctural but hafnium nitrate 

Eight O atoms form a dodecahedron around the Ti and the 4 N atoms form a flattened tetrahedron. 

In oxidation states lower than -t-4, only Ti forms a sulfate and this gives rise to the alums, MTi(S04)2-12H20 (M = Rb, Cs), containing the octahedral hexaaquotitanium(III) ion. 

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Out of the Cd compounds with oxoanions of elements of group 16, the trimorphic CdS03 is to be mentioned, with different six-coordinate Cd in each of the three phases.289... 

The elements form an enormous range of compounds with oxoanions, many of those with calcium (carbonate, silicate,... 

The elements form an enormous range of compounds with oxoanions, many of those with calcium (carbonate, silicate, phosphate, sulfate) being common minerals in the Earth s crust. Hydrated forms are common. Their thermal stability towards decomposition to the oxide is less than that for the alkali metals, and increases with cation size. Thus Be (like Al) does not form a stable carbonate the decomposition temperatures for the others range from 400°C for MgC03 to 1400°C for BaC03. 

Among the compounds in which I + is combined with oxoanions are I(0S02F)3, I(N03)3, l(OCOCH3)3, IPO4, and 1(0003)3 (equations 133-137). These compounds contain essentially covalent I-O bonds. Preparative routes are shown as followings. These compounds are very sensitive to moisture and are not stable much above room temperature. They are hydrolyzed with disproportion of the 1 +, as shown for IPO4 (equation 138). 

Actinyl compounds with tetrahedral oxoanions TO4 (T = S, Cr, Se, Mo) that are based upon 3D networks of comer-sharing coorination polyhedra are listed in Table 9. To proceed with their stmctural description, we shall use graph theory analysis of heteropolyhedral frameworks as developed in [221], It turns out that the most actinyl-based 3D units with comer-sharing between chemically different polyhedra can be described as based upon ID stmctural elements for which we adopt the term fundamental chain suggested by Liebau [222] for tetrahedral frameworks in silicates and related materials. However, some actinyl oxosalt stmctures are better described as consisting of polymerized 2D sheets. For convenience, the frameworks will be classified into three major groups (1) frameworks based upon fundamental chains (2) microporous chiral uranyl molybdate frameworks (3) frameworks based upon 2D sheets. 

Actinide compounds with heavy oxoanions containing a stereochemically active lone-pair of electrons... 

The purpose of this chapter is to address the role of heavy oxoanions containing a chemically inert, but stereochemically active, lone-pair of electrons on the structures of purely inorganic actinide compounds. This work is not intended to be a comprehensive survey of all compounds that fall into this class, but rather its goal is to highlight key compounds with atypical structures where the influence of the lone-pair of electrons can be ascertained, if only in part. 

Actinide compounds with heavy oxoanions containing a stereochemically. .. 2.3. Tls (U02)2lTe20s(0H)](Te20S-2H20 [27]... 

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