[xshadow]

I'll have to do this mini- experiment:
TiCl₄ in HCl (15%) ,than I add NH₃ in excess

The reaction should be:

NH₃ + HCl  ----> NH₄⁺ + Cl^-
NH₃ is in excess.
So in the solution I'll have OH^- (basic pH) ,some NH₃ ,some Cl^- and TiCl₄


Now different things I think they may happen:

1) TiCl₄ + 2OH^-  ---> [ TiCl₄OH₂ ] ^2-  ( I think Titanium can do exacohordinated complex)
2)TiCl₄ + 2OH^- ----> Ti(OH)₄  (ligand excanche)
3)Ti(OH)₄  + 2 OH^- ----> Ti(OH)₆  2-


a) Now I  check and I found that the 2) happens.... formation of the complex TI(OH)₄  (is a complex??...or a ionic compound??!) and then precipitation
Why  the 1) and 2) can't occour-----

b) in a solution of TiCl4 in HCl (15%) I have only TiCl4...or I have also some TI4+ free (complexation equilibrium)

thanks

[chenbeier]

TiCl₄ will react with water or hydoxide directly to TiO₂,  nothing between will be get.
Its getting big white nebula fumes.

[AWK]

I guess you don't understand what an optimized chemical procedure means.
If you have read the recommended 3 pages of the Brauer texbook, his procedure use slightly dilute hydrochloric acid (approx. 33%), temperature of 0°C, ammonium chloride, titanium tetrachloride, and then the solution is saturated with gaseous hydrogen chloride to precipitate yellow ammonium hexachlorotitanate (note - the compound is only stable in the presence of very concentrated hydrochloric acid and only with saturated HCl the solution this compound precipitates). Attempting to dry the compound decomposes it. Hydrolysis occurs at lower concentrations of hydrochloric acid (temporarily with the formation compound with Ti-O-Ti bond) or leads to complete hydrolysis.

[xshadow]

I guess you don't understand what an optimized chemical procedure means.
If you have read the recommended 3 pages of the Brauer texbook, his procedure use slightly dilute hydrochloric acid (approx. 33%), temperature of 0°C, ammonium chloride, titanium tetrachloride, and then the solution is saturated with gaseous hydrogen chloride to precipitate yellow ammonium hexachlorotitanate (note - the compound is only stable in the presence of very concentrated hydrochloric acid and only with saturated HCl the solution this compound precipitates). Attempting to dry the compound decomposes it. Hydrolysis occurs at lower concentrations of hydrochloric acid (temporarily with the formation compound with Ti-O-Ti bond) or leads to complete hydrolysis.

My slides say that   there will be the precipitation of Ti(OH)4 using HCl + NH3 in excess..

but I don't understand why is formed Ti(OH)4 and not for example  TiCl4(OH)2 ^2-   or Ti(OH)6 ^2- ecc
Don't find any logic ...logic that I found in organic chemistry 

[AWK]

The product of the hydrolysis with ammonia will likely be hydrated titanium oxide. It can be completely dehydrated at temperatures over 300°C.

[xshadow]

The product of the hydrolysis with ammonia will likely be hydrated titanium oxide. It can be completely dehydrated at temperatures over 300°C.

Thanks!