Luteocobalt —

Luteocobaltic chloride (modern, [Co(NH3)6]C13, hexaamminecobalt(III) chloride) is a stable yellow-orange compound.55 In solution, all the chlorine is immediately precipitated by silver nitrate. Treatment with hydrochloric acid at 100 °C does not remove any ammonia. Treatment with sulfuric acid does not remove any ammonia, but yields the compound Co2(S04)3T2NH3, i.e. the chlorine atoms are replaced by sulfate groups. Clearly, some sort of very stable metal—ammonia bonding but much less stable metal—chlorine bonding is indicated. 

Luteocobalt chloride No immediate pp. Reddish-yellow pp. No immediate pp. 

Linkage isomerization reactions, 465 Linked redox centres, 493 Liquid-liquid extraction, 538-549 Lowry, Thomas Martin, 16 Luteocobalt—see Cobalt, hexaammine-Luteocobaltic chloride —see Cobalt, hexaammine-, chloride... 

This is shown in the following Table 2, in which fourteen colloids are listed in the order of decreasing reciprocal hexol number. The table contains information on the flocculability with six different salts, viz., hexol nitrate (6—1) rhodochromium chloride (5—1) platinium triethylenediamine tetranitrate (4—1) luteocobalt chloride (3—1) CaCl2(2—1) and NaCl(l—1). 

Hence, for example, in the complex ion hexamminecobalt(III), [Co (NH3)6] + (Werner s luteocobaltic complex), the central nucleus is the cobalt atom and the ammoniac molecules are the ligands. We can already notice that in the formula of a complex, the complex is written between brackets (for details about the writing and nomenclature of complexes, see Sect. 22.4). 

According to Werner, ligands are spatially distributed around the metallic ion. If, for example, we are considering the complexes of coordinence 6, they are distributed at the summits of a regular octahedra whose center is occupied by the coordinator metal. This is the case with the hexamminecobalt(III) cation [Co(NH3)6] + (Werner s luteocobaltic complex) (Fig. 23.2). In general, a coordinence number is associated with one or several particular geometries of the complex. For example, the complexes of Cu(I), Ag(I), Au(I), and Hg(II) are... 

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