Arsenic toxicity: an atom counting and electrophilicity-based protocol.

The atomic number (Z) and electrophilicity index (omega) have been utilized to explain the toxicity of various alkali and transition-metal ions as well as to predict that of the arsenic ions. The toxicity of two different training sets of arsenic derivatives is described using the global electrophilicity (omega) and number of nonhydrogenic atoms (N (NH)) along with the local philicity (omega(As)+) and the atomic charge (Q (As)) on the arsenic atom. Applying the regression models from the training sets, toxicity of some unknown arsenic derivatives is predicted.