Question

The formula of dichloro bis (urea) copper (II) is
(A) \[\text{ }[Cu{{(O=C{{(N{{H}_{2}})}_{2}})}_{2}}]\text{ }C{{l}_{2}}]\]
(B) \[[CuC{{l}_{2}}{{(O=C{{(N{{H}_{2}})}_{2}})}_{2}}]\]
(C) \[[Cu(O=C{{(N{{H}_{2}})}_{2}})]\text{ }Cl~\]
(D) \[[CuC{{l}_{2}}(O=C{{(N{{H}_{2}})}_{2}}){{H}_{2}}]~\]

Answer 1

Hint: Given name is according to IUPAC naming rule for coordination complexes, according to which, number (di, tri, tetra, and so on) and name of ligands is written first (if more than one ligands then the name is written in alphabetical order). After its central metal name is written an oxidation state of the central metal is written next to its name.

Complete Step by Step Solution:
As per the given name dichloro bis(urea) copper (II), there are two chlorine elements, dichloro (ligand chlorine is written as chloro according to IUPAC rules, replacing one of chlorine with o) such as\[C{{l}_{2}}\]. As di is used for indicating the number of chlorine ligands, bis is also used to indicate number two if any other ligand is present (urea). Thus, there are two urea compounds as \[~{{(O=C{{(N{{H}_{2}})}_{2}})}_{2}}\].

Thus there are four ligands, two are chlorine and the other two are urea. After this Cu is written as copper metal representing central metal with an oxidation state of +2. This means copper in this complex compound is in oxidation state Cu(II) or\[C{{u}^{+2}}\]. Copper is surrounded by all four ligands, donating an electron to it through a coordinate bond such as \[[CuC{{l}_{2}}{{(O=C{{(N{{H}_{2}})}_{2}})}_{2}}]\]. Due to the accepting tendency of copper metal, it attains a positive charge (cation) of the oxidation state of +2.

Thus, the correct option is B.

Note: It is important to note that a compound or any salt is formed by two ions, cation (positive charge) and anion (negative charge). IUPAC name and molecular formula are always written with cation in the first place and then anion in second place such as cation-anion\[(N{{a}^{+}}C{{l}^{-}})\].