Cadmium covalent radius

In other crystals an octahedral metal atom is attached to six non-metal atoms, each of which forms one, two, or three, rather than four, bonds with other atoms. The interatomic distance in such a crystal should be equal to the sum of the octahedral radius of the metal atom and the normal-valence radius (Table VI) of the non-metal atom. This is found to be true for many crystals with the potassium chlorostannate (H 61) and cadmium iodide (C 6) structures (Table XIB). Data are included in Table XIC for crystals in which a tetrahedral atom is bonded to a non-metal atom with two or three covalent bonds. The values of dcalc are obtained by adding the tetrahedral radius for the former to the normal-valence radius for the latter atom. 

The ionic radius of chlorine has the value 1.81 A (Chap. 13). The following distances between chlorine atoms of different molecules have been observed in the molecular crystal 1,2,3,4,5,(Whexachlorocyclo-hexane.-57 3,60, 3.77, 3.82 A these are close to twice the ionic radius. Similar agreement is shown by many other organic crystals and inorganic covalent crystals. Cadmium chloride, for example, consists of... 

Cadmium. Cadmium appears to be compatible or very mildly incompatible, similar to zinc. Almost nothing is known about which minerals it prefers. From a crystal-chemical view, cadmium has similar ionic radius and charge to calcium, but a tendency to prefer lower coordination due to its more covalent bonding with oxygen (similar to zinc and indium). Cadmium in spinel Uierzolites varies from 30 ppb to 60 ppb (BVSP) and varies in basalts from about 90 ppb to 150 ppb (Hertogen et al., 1980 Yi et al., 2000). Cd/Zn is —10 in peridotites (BVSP) and the continental cmst (Gao etal., 1998), and —1.5 X 10 in basalts (Yi etai, 2000). We adopt the mean of these ratios (1.2 X 10" ). 

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