Titanium triiodide

Titanium Triiodlde. Titanium triiodide is a violet crystalline soHd having a hexagonal unit cell (146). The crystals oxidize rapidly in air but are stable under vacuum up to 300°C above that temperature, disproportionation to the diiodide and tetraiodide begins (147). 

Titanium triiodide can be made by direct combination of the elements or by reducing the tetraiodide with aluminum at 280°C in a sealed tube. Til reacts with nitrogen, oxygen, and sulfur donor ligands to give the corresponding adducts (148). 

The reduction of titanium tetraiodide by triisobutylaluminum (Al/Ti = 1) was reported by Moyer (1965) to be analogous to the reduction of the tetrachloride [Eq. (35) ]. Unlike the chloride system at this ratio, however, the iodide system is essentially inactive (Saltman and Link, 1964 Moyer and Lehr, 1965). Evidently, the concentration of diisobutylaluminum iodide is too low for alkylation or coordination to occur with titanium triiodide. This follows because an excess of the aluminum compound (Al/Ti >2) finally produced some activity. These conclusions are substantially in agreement with those of Saltman and Link (1964) who reasoned that a strong alkylating agent, such as triisobutylaluminum, was essential for activity. 

Specific indicators owe their behavior to a reaction with one of the participants in the titration. The best-known specific indicator is starch, which forms a dark blue complex with triiodide ion. Also, potassium thiocyanate is used as a specific indicator, for example, in titration of iron(III) with solutions of titanium(III) sulfate. 

TiCI4[g] TITANIUM TETRACHLORIDE (GAS) 1679 Tml3[g] THULIUM TRIIODIDE (GAS) 1723... 

CgHj4CI3N12O1sTi, Hexaureatitanium perchlorate, 38B, 952 CgH2413N120eTi, Hexakis(urea)titanium(III) iodide, 35B, 630 CgH24I3N120gV, Hexaureavanadium triiodide, 38B, 953 CgH24N14O12Zn, Hexaureazinc nitrate, 38B, 954... 

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