Penamaan Senyawa Koordinasi/Senyawa Kompleks

Senyawa kompleks di mana ion logam bersenyawa dengan gugus fungsi molekul netral atau anion yang disebut ligand.

Tata cara penamaan senyawa kompleks sbb :
1. Untuk memberikan nama senyawa koordinasi, apapun bentuk senyawa koordinasi, baik itu berupa kation
    atau anion, selalu menyebutkan kation terlebih dahulu dari anion.
2. Dalam memberikan nama ion kompleks :
    a. Ligand disebutkan pertama kali, dalam urutan alpabet kemudian dilanjutkan dengan ion logam.
    b. Berikut beberapa nama Ligand

Ligand Anion	Nama		Ligand Netral	Nama
Br-	bromo		NH3	ammine
F-	fluoro		H2O	aqua
O2-	oxo		NO	Nitrosyl
OH-	Hydroxo		CO	Carbonyl
CN-	cyano		O2	dioxygen
C2O42-	oxalato		N2	dinitrogen
CO32-	carbonato		C5H5N	pyridine
CH3COO-	acetato		H2NCH2CH2NH2	ethylenediamine

    c. Untuk jumlah berapa banyak anion atau kation berikatan gunakan bahasan latin seperti

Jumlah	Prefix	Jumlah	Prefix	Jumlah	Prefix
1	mono	5	penta (pentakis)	9	nona (ennea)
2	di (bis)	6	hexa (hexakis)	10	deca
3	tri (tris)	7	hepta	11	undeca
4	tetra (tetrakis)	8	octa	12	dodeca

    d. Beri nama untuk ion pusat/ion metal.

Nama Logam	Nama Dalam Senyawa Anion Kompleks
Iron	Ferrate
Copper	Cuprate
Lead	Plumbate
Silver	Argenate
Gold	Aurate
Tin	Stannate

Berikut beberapa contoh penamaan :

1. [Cr(NH₃)₃(H₂O)₃]Cl₃

Jawab: triamminetriaquachromium(III) chloride
Pembahasan: Ion kompleks berada di dalam tanda kurung, disebut sebagai kation.
Ligand ammine ditulis sebelum ligand aqua berdasarkan urutan alpahabet.
Karena ada 3 chlorides yang berikatan dengan ion kompleks, maka muatan ion kompleks adalah +3 (Karena senyawa bermuatan netral).
Dari muatan ion kompleks dan muatan dari ligand, kita bisa menghitung bilangan oksidasi dari ion logam. Pada contoh ini, semua ligand adalah molekul netral. Sehingga, bilangan oksidasi dari kromium adalah +3.

2. [Pt(NH₃)₅Cl]Br₃

Jawaban: pentaamminechloroplatinum(IV) bromide
Pembahasan: The complex ion is a cation, the counter anion is the 3 bromides.
The charge of the complex ion must be +3 since it bonds with 3 bromides.
The NH₃ are neutral molecules while the chloride carries - 1 charge. Therefore, the oxidation number of platinum must be +4.

3. [Pt(H₂NCH₂CH₂NH₂)₂Cl₂]Cl₂

Answer: dichlorobis(ethylenediamine)platinum(IV) chloride
Solution: ethylenediamine is a bidentate ligand, the bis- prefix is used instead of di-

4. [Co(H₂NCH₂CH₂NH₂)₃]₂(SO₄)₃

Answer: tris(ethylenediamine)cobalt(III) sulfate
Solution: The sulfate is the counter anion in this molecule. Since it takes 3 sulfates to bond with two complex cations, the charge on each complex cation must be +3.
Since ethylenediamine is a neutral molecule, the oxidation number of cobalt in the complex ion must be +3.
Again, remember that you never have to indicate the number of cations and anions in the name of an ionic compound.

5. K₄[Fe(CN)₆]

Answer: potassium hexacyanoferrate(II)
Solution: potassium is the cation and the complex ion is the anion.
Since there are 4 K⁺ binding with a complex ion, the charge on the complex ion must be - 4.
Since each ligand carries –1 charge, the oxidation number of Fe must be +2.
The common name of this compound is potassium ferrocyanide.

6. Na₂[NiCl₄]

Answer: sodium tetrachloronickelate(II)
Solution: The complex ion is the anion so we have to add the suffix –ate in the name of the metal.

7. Pt(NH₃)₂Cl₄

Answer: diamminetetrachloroplatinum(IV)
Solution: This is a neutral molecule because the charge on Pt⁺⁴ equals the negative charges on the four chloro ligands.
If the compound is [Pt(NH₃)₂Cl₂]Cl₂, eventhough the number of ions and atoms in the molecule are identical to the example, it should be named: diamminedichloroplatinum(II) chloride, a big difference.

8. Fe(CO)₅

Answer: pentacarbonyliron(0)
Solution: Since it is a neutral complex, it is named in the same way as a complex cation. The common name of this compound, iron carbonyl, is used more often.

9. (NH₄)₂[Ni(C₂O₄)₂(H₂O)₂]

Answer: ammonium diaquabis(oxalato)nickelate(II)
Solution: The oxalate ion is a bidentate ligand.

10. [Ag(NH₃)₂][Ag(CN)₂]

Answer: diamminesilver(I) dicyanoargentate(I)
You can have a compound where both the cation and the anion are complex ions. Notice how the name of the metal differs even though they are the same metal ions.

Can you give the molecular formulas of the following coordination compounds?

1. hexaammineiron(III) nitrate
2. ammonium tetrachlorocuprate(II)
3. sodium monochloropentacyanoferrate(III)
4. potassium hexafluorocobaltate(III)

Can you give the name of the following coordination compounds?

5. [CoBr(NH₃)₅]SO₄
6. [Fe(NH₃)₆][Cr(CN)₆]
7. [Co(SO₄)(NH₃)₅]⁺
8. [Fe(OH)(H₂O)₅]²⁺

Answers:

1. [Fe(NH₃)₆](NO₃)₃
2. (NH₄)₂[CuCl₄]
3. Na₃[FeCl₁(CN)₅]
4. K₃[CoF₆]
5. pentaamminebromocobalt(III) sulfate
6. hexaammineiron(III) hexacyanochromate (III)
7. pentaamminesulfatocobalt(III) ion
8. pentaaquahydroxoiron(III) ion