WHY ARE (MGO)(N) CLUSTERS AND CRYSTALLINE MGO SO REACTIVE

The electronic structures and chemical reactivities (toward H, Li, Li- 2, and H-2) are examined for small (MgO)(n) clusters. It is postulated that decreases in the clusters' reactivity toward the above prototypi cal species as the cluster size (n) increases is related to the decrea se in valence unsaturation that accompanies increases in n. Further, i t is suggested that the known high reactivity of MgO powder and crysta l is likely related to surface or defect sites that possess high level s of valence unsaturation.