  Classical contact Lie algebras are the fundamental algebraic structures on
the manifolds of contact elements of configuration spaces in classical
mechanics. Xu introduced a large category of contact simple Lie algebras which
are related to locally finite derivations and are in general not finitely
graded. The isomorphism classes of these Lie algebras were determined in a
previous paper by Xu and Su. In this paper, the derivation algebras and the
2-cohomology groups of these Lie algebras are determined, and it is obtained
that the 2-cohomology groups of these Lie algebras are all trivial.
