Hullo,

If I could put water in a container strong enough to withold the pressure, could the water still freeze being unable to expand ?...or is that impossible and nothing can contain it ?

There has been a thread exactly on this question on an italian forum of physics, 2 months ago.

Given the known values for water of :

thermic dilatation coefficient at constant P: a = (1/V)(∂V/∂T)

_{P}isothermal compressibility coefficient: k = -(1/V)(∂V/∂P)

_{T}Clapeyron coefficient: b = dP/dT at equilibrium between the two phases

It's possible to compute the pressure variation with temperature at constant volume:

w = (∂P/∂T)

_{V} since it can be proven that w = a/k

and then we cam compare it with b.

a = -1*10

^{-4} K

^{-1} at P = 1 atm, T = 273 K

k = 4.6*10

^{-10} Pa

^{-1} at P = 1atm

b = -1.3*10

^{7} Pa/K.

So w = -2.1*10

^{5} Pa/K

Then, since it results that |w| < |b|, water cannot remain in the liquid form = must freeze.

Non-intuitive result, indeed.