  We obtain solutions of the three dimensional Dirac equation for radial
power-law potentials at rest mass energy as an infinite series of square
integrable functions. These are written in terms of the confluent
hypergeometric function and chosen such that the matrix representation of the
Dirac operator is tridiagonal. The "wave equation" results in a three-term
recursion relation for the expansion coefficients of the spinor wavefunction
which is solved in terms of orthogonal polynomials. These are modified versions
of the Meixner-Pollaczek polynomials and of the continuous dual Hahn
polynomials. The choice depends on the values of the angular momentum and the
power of the potential.
