Equation of State for Solids (Dense Fluids?)

[JackPunchedJi]

Stumbled across an old journal a few weeks ago that suggested the equation of state for a solid could be written:

V[P,T] = Vi - (C1)P + (C2)T

with an internal energy:

U[P,T] = (C3)T - (C2)PT

C1, C2, C3 being constants of course.

Does this make logical sense? It seems awfully simplified. I would assume there would be some non-linear terms in the equation of state itself (such as a T^2 or PT). Can't seem to find the paper either, but would love to look over it again if anyone is aware of what I am ranting about.

 

[Gordianus]

It looks like a linearized (Taylor expansion) equation of state.
The solid has a nominal volume Vi and I know that if increase the pressure the volume should reduce (thus the sign) but, if I increase the temperature the solid expands.
Very simple indeed, it should be valid for small changes of p and T.

 

[JackPunchedJi]

Does the relation to evaluate the internal energy of this equation of state seem valid? It's been a while since I've taken a thermo course.