The second group metals

Metal Pauling Electronegativity Ethers Reaction of R2M with COi RCOCl HoO 02 

The organic derivatives of the most electropositive elements of Group II—Ca, Sr, Ba—have been little studied, and only a very limited amount of reliable information is available. Organic derivatives of calcium appear to resemble somewhat those of lithium, for example, in respect of attack on ethers and on olefins. 

Magnesium and beryllium form organic derivatives which are essentially covalent in structure and highly reactive, the M—C bonds being strongly polarized they resemble organolithium compounds in several respects. 

The special place occupied by the Grignard reagents is due both to their reactivity (coupled with stability in ether solution, unlike RLi) and the comparative ease of their preparation from metallic magnesium, which itself is exceptional among the more electropositive metals in being readily available and requiring little or no cleaning from corrosion products before use. 

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Two groups of experiments were carried out. The first group samples were non-metalized and placed on metal p>ads and the ones from the second group - metalized on one side. All samples were corona charged to the initial value of about 660V for the surface potential. The samples were then placed in a vacuum chamber at pressure of O.lmbar for 30 minutes. The results obtained are paesented in Table 1, where Vq is the initial surface potential and V is the surface pxjtential measured just after the samples were taken out of the vacuum chamber. 

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