Oxyhalide complexes

Various anionic complexes have been made [26a]  

Reaction of Ph4PCl with 0s04 gives Ph4P+0s04Cr, the anion having a tbp structure with a very long equatorial Os—Cl bond (2.76 A) [45]. 

Both ruthenium and osmium form tram-M02X4 species (X = Cl, Br), for example 

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No complexes have at present been authenticated in oxidation states greater than +6, whereas oxyhalide complexes exist where the +8 state is known this parallels trends in the halides and oxyhalides. 

Halide and oxyhalide complexes of elements of the titanium, vanadium and chromium sub-groups. 

Oxyhalide Complexes. (Ph4A)[Cr03X] (A = P or As and X = F or Cl) have been precipitated from a solution of the corresponding potassium salt in dilute HF or HCl and their unit cells, i.r., and electronic spectra reported.The interactions of Cr02Cl2 with aromatic hydrocarbons and fluorocarbons have been examined and the intermolecular charge-transfer transitions recorded. 

In these oxyhalide complexes, the inter-halide distances between layers are smaller than the sum of the ionic radii of the halides (Table 11). In the oxybromides and ox5dodide series the M—Br (next layer) and M—I (next layer) distances increase (Table 11) with increase in parameter c (Table 10) as these distances depend solely on the dimensions of the c-axis. In the oxychloride series the M—Cl (next layer) distance, however, show a decrease along the lanthanide series. So does the parameter c (Table 10). This is the reason why the oxychlorides of Tm, Yb and Lu cannot maintain the PbFCl type structure. 

A. A. Khokhryakov and A.M. Khokhlova, IR Spectra of Emission of Oxyhalide Complex Groups of S-Elements in Molten Mixtures of Alkali Metal Halides, Rasplavy N6 (1989) 66-71. 

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