Question

Which of the following name formula combinations is not correct ?
A.$K\left[ {Cr{{\left( {N{H_3}} \right)}_2}C{l_4}} \right]$ Potassium diammine tetra chlorochromate$({\rm I}{\rm I}{\rm I})$
B.$\left[ {Co{{\left( {N{H_3}} \right)}_4}\left( {{H_2}O} \right)I} \right]S{O_4}$ Tetraammineaquaiodocobalt$({\rm I}{\rm I}{\rm I})$ sulphate
C.${K_2}\left[ {Pt{{(CN)}_4}} \right]$ Potassium tetracyanoplatinate$\left( {{\rm I}{\rm I}} \right)$
D.${\left[ {Mn{{\left( {CN} \right)}_5}} \right]^{2 - }}$ Pentacyano Manganate$\left( {{\rm I}{\rm I}} \right)$ ion

Answer 1

Hint: For solving this question we should remember complete IUPAC rules for nomenclature of coordination compounds . There should be a single letter gap between both the ions i.e. complex ion and simple ions . To name a coordination compound , no we should take care of cation and anion because cation is always named before the anion .

Complete step by step answer:
Some basic rules we should check in this question are :
 For the coordination sphere we should name the ligands in alphabetical order. If we cross check this rule in every option we do not find any fault .
For anionic ligands we use “o” in the end like “chloro for chloride , iodo for iodide” and for neutral ligands common name is used but for water we use aqua and for ammonia we use ammine . Again this rule is satisfied by all options .
For denoting the number of ligands we use Greek prefixes e.g. di- , tri-and tetra etc. Again if we cross check this rule in every option we do not find any fault .
 After naming the ligands we name the central metal . If the complex ion is cation then the metal is named the same as the element but the complex ion is anion then the name of metal ends with the suffix “-ate” . This rule is also satisfied by all options .
After naming metal the oxidation state of metal in complex is given as a Roman numeral in parentheses . After cross checking this rule we find that in option (D) oxidation state of manganese is $ + 3$ but in the name it is written $ + 2$ .
Hence option (D) is the correct answer .

Note:
We should take care of ligands like water and ammonia because we use the name aqua instead of water and amine instead of ammonia. Also we should notice that there is double “m” in ammine .Ammine is (inorganic chemistry) any of a class of coordination compounds in which ammonia acts as a ligand while amine is (inorganic chemistry) a functional group formally derived from ammonia by replacing one, two or three hydrogen atoms with hydrocarbon or other radicals.