  We present a unified account of magnetic exchange and Raman scattering in the
quasi-one-dimensional transition-metal oxide NaV$_2$O$_5$. Based on a
cluster-model approach explicit expressions for the exchange integral and the
Raman-operator are given. It is demonstrated that a combination of the
electronic-structure and the Dzyaloshinskii-Moriya interaction, allowed by
symmetry in this material, are responsible for the finite Raman cross-section
giving rise to both, one- and two-magnon scattering amplitudes.
