Question

For inorganic chemistry

What is the correct name of the following :

1- [Ni(Co)4]

2- [Co(NH3)6] ^2+

3- [ Co(NH3)3 (H2O)2 Cl] Br2

4- Na3 [ Co(NO2)6 ]

Answer 1

Hi,

You have to consider whether the complex has an overall positive charge or an overall negative charge while naming the complex ions.
If the complex is positive, it will be written first in the ionic formula. Start by identifying the central metal atom and its oxidation state. This can be tricky because if some of the ligands (groups attached to the central metal atom) are anions, that will affect the overall charge.

Name the ligands first in naming a complex cation, using the following rules:

1. Ligands are named first in each complex ion.

2. A special code name is assigned to each ligand. For eg:
Ligand: Code Name
H2O: aqua
NH3: ammine
OH(-): hydroxo
Cl(-): chloro
F(-): fluoro
CN(-): cyano
C2O4(2-): oxalato

3. If there is more than one of a particular ligand, add prefixes like di-, tri-, tetra-, penta-, or hexa- .

4. If there is more than one TYPE of ligand present, name them in alphabetical order (not including the prefixes). For eg, triammine would come before dichloro.

5. When all the ligands have been named in the proper order, attach the central metal ion's name. If this metal can have more than one oxidation state (as most transition metals can), you should include a Roman numeral in parentheses to indicate the charge of the central ion. If the ion has only one possible oxidation state (like Al(3+)), then a Roman numeral is not necessary.

When naming complex anions, the rules are essentially the same, except you change the metal ion's name to end in -ate.

1- [Ni(Co)4] = tetracarbonylnickel

2- [Co(NH3)6] ^2+ = Hexamminocobalt ion

3- [ Co(NH3)3 (H2O)2 Cl] Br2 = Triamminediaquachlorido cobalt(III) bromide

4- Na3 [ Co(NO2)6 ]= Sodium hexanitritocobaltate(III)