Naming Complex Ions and Questions To Try

Rules for naming the complex ion when given the formula in square brackets eg:  [Fe(CN)6]4-

Rules :
Name the ligands first, in alphabetical order, then the metal atom or ion. 
Note: The metal atom or ion is written before the ligands in the chemical formula.
For negatively charged ligands the endings change as follows: "ide" becomes "-ido"
"ate" becomes "-ato"
"ite" becomes "-ito"
so for example  chloride becomes chlorido, bromide becomes bromido, fluoride becomes fluorido, hydroxide becomes hydroxido, cyanide CN- becomes cyanido and C2O42- oxalato
For neutral ligands, the name of the molecule is used. Watch out for tricky ones like H2NCH2CH2NH1,2 diammino ethane).  Important exceptions: water is called ‘aqua’, ammonia is called ‘ammine’, carbon monoxide is "carbonyl" and nitrogen monoxide "nitrosyl".

3. If there are more than one of each type of ligand then Greek prefixes are used to designate the number of each type of ligand in the complex ion, e.g. di-, tri-, tetra-, penta-, hexa- and hepta-.

Numerical Prefixes
di, tri, tetra, penta, hexa, hepta and octa

4. After naming the ligands, name the central metal. If the complex ion is a positively charged ion overall, the metal is named the same as the element. For example,  Co is called cobalt and Pt is called platinum, copper is called copper. However, if the complex ion is a negative ion overall then the name of the metal should end with the  –ate.  For example, Co in a negative ion complex is called cobaltate and Pt is called platinate. For some metals, the Latin names are used in e.g. Fe is called ferrate and Cu becomes cuprate
5 The oxidation state of the metal is then added in Roman Numerals.

Test yourself – get the name from the formula :
Question 1      [Cr(NH3)3(H2O)3]3+
Question 2       [Pt(NH3)5Cl]3+
Question 3      [Fe(CN)6]4-
Question 4        [NiCl4]2-

Answers below .....

Question - Get the Formula of the complex ion from the Name
When writing the formula of a complex ion when given the name, a different set of rules applies :
The symbol of the metal is written first, then negatively charged ligands, followed by the neutral ligands:

Question 1  hexaammineiron(III)
Question 2  tetrachloridocuprate(II)
Question 3  hexafluoridocobaltate(III)
Question 4  tetraaquadihydroxidoiron(III)
Question 5  tetraamminediaquacopper(II) ion.

Answers below ....

Answers to "Get the name from the Formula"

Answer 1  triamminetriaquachromium(III)
Answer 2  pentaamminechloridoplatinum(IV)
Answer 3   hexacyanidoferrate(II)
Answer 4  tetrachloridonickelate(II)

Answers to "Get the Formula of the complex ion from the Name"
Answer 1  [Fe(NH3)6]3+
Answer 2  [CuCl4]2-
Answer 3  [CoF6]3-
Answer 4 [Fe(H2O)4(OH)2]+
Answer 5  [Cu(NH3)4(H2O)2]2+