text: Mixed alkyl/aryl-halide compounds, which contain a single C-M bond and a C-X bond, are typically prepared by oxidative addition. Magnesium-containing compounds of this configuration are known as the Grignard reagents, though some calcium Grignards are known and more reactive and sensitive to decomposition. Calcium grignards must be pre-activated prior to synthesis.
  There are three key reaction pathways for dialkyl and diaryl group 2 metal compounds.
  *metathesis:
  :MX + R-Y &rarr; MR + Y-X'
  *transmetallation:
  :MR + M &rarr; MR + M
  *via the Schlenk equilibrium:
  :2 RMX &rarr; MR + MX