Ionic bonds, toxicology

As discussed in Section 12.2, group 1A metals form ionic metal-carbon bonds. Organometallic compounds of group 1A metals other than lithium have metal-carbon bonds with less of a covalent character than the corresponding bonds in lithium compounds and tend to be especially reactive. Compounds of rubidium and cesium are rarely encountered outside the laboratory, so their toxicological significance is relatively minor. Therefore, aside from lithium compounds, the toxicology of sodium and potassium compounds is of most concern. 

Turner, J.E., M.W. Wilhams, K.B. Jacobson, and B.E. Hingerty. 1985. Correlations of acute toxicity of metal ions and the covalent/ionic character of their bonds. In QSAR in Toxicology and Xenobiochemistry, edited by M. Tichy, 171-178. Amsterdam Elsevier. 

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