Question
Wed February 15, 2012 By: Sphurti

WHAT IS THE DIFFERENCE BETWEEN PRIMARY AND SECONDARY VALENCY OF A COORDINATION COMPOUND? WHAT IS THE PRIM. AND SEC. VALENCY OF[Pt(NH3)6]Cl4 ???

Expert Reply
Thu February 16, 2012
 

The 

primary valence is the number of negative ions needed to satisfy the charge on the metal ion. In

  • CoCl3 6 NH

 the cobalt(III) complexe three Cl- ions are needed to satisfy the primary valence of the Co3+ ion.

The secondary valence is the number of ions of molecules that are coordinated to the metal ion. Werner assumed that the secondary valence of the transition metal in these cobalt(III) complexes is six.

[Pt(NH3)6]Cl4 

In this complex the primary valency is 4; and the secondary valency is 6.

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