title: Titanium(III) iodide
text: # Titanium(III) iodide
  
  Titanium(III) iodide is an inorganic compound with the formula $TiI_3.$ It is a dark violet solid that is insoluble in solvents, except upon decomposition.
  
  ## Preparation and structure
  
  Titanium(III) iodide can be prepared by reaction of titanium with iodine:
  
      $\mathrm {2\ Ti+3\ I_{2}\longrightarrow 2\ TiI_{3}}$
  
  It can also be obtained by reduction of $TiI_4,$ e.g., with aluminium.
  
  In terms of its structure, the compound exists as a polymer of face-sharing octahedra. Above 323 K, the Ti---Ti spacing are equal, but below that temperature, the material undergoes a phase transition. In the low temperature phase, the Ti---Ti contacts are alternating short and long. The low temperature structure is similar to that of molybdenum tribromide.
  
  