van der Waals equation of state constants

In the van der Waals eqn. for real gases the coefficients a and b are used in the respective correction terms of pressure and volume wrt to ideal gas eqn.

Is the value of the van der Waals coefficients dependent or independent of the absolute temperature or not?

• The "formal" constants are just that - constants. However one could certainly have a table of $a$ and $b$ values for different ranges of temperature and pressure. See wikipedia article real gas for other equations. en.wikipedia.org/wiki/Real_gas – MaxW Oct 10 '16 at 20:11

${a = \frac{27 R^2 T_c^2} {64 P_c}}$
${b = \frac{R T_c }{ 8 P_c}}$
Since, $T_c$ and $P_c$ are constants, we can conclude that the van der waals constants are really "constants."