The chemical effects of ultrasound are reviewed with a focus on organometallic systems. Acoustic cavitation is the principal source of sonochemistry, but its nature is quite dependent on the local environment. Cavitational collapse in homogeneous liquids generates hot spot heating of approximately equals 5200K, which can cause multiple ligand dissociation, clusterification, and initiation of homogeneous catalysis. Cavitation near solids has much different effects due to microjet impact on the surface; enhancement of a wide variety of liquid-solid reactions and heterogeneous catalysis occur. These unusual reaction patterns are compared to other high energy processes.