6.5: Nomenclature of Coordination Complexes

Systems of nomenclature and formulae are intended as tools, to be employed insofar as they are useful

There are well-established rules for both naming and writing the formulae of coordination compounds. The purpose of these rules is to facilitate clear and precise communication among chemists. As with all such rules, some are more burdensome than others to employ, and some serve more crucial roles in the communication process while others are more peripheral - and all are poorly used in the service of pedantic tyranny, especially when used against those who are otherwise doing good work. For this reason, you are urged to approach the rules in a spirit of generosity towards others in

• naming and writing formulas as reasonably accurately as you can so that ligands and metals are where readers expect them and thus can understand what you mean more easily.
• being gracious towards the many professional inorganic chemists who adhere loosely to some of the rules you are about to learn.

recognizing that in cases when a structure is particularly complex and a picture may make be particularly useful, you should supply one (See the note below).

Note: Sometimes the most helpful name to give a compound is 42.

Even though the IUPAC nomenclature rules permit specification of even the most complex structures, it is often much easier and more effective to supply a numbered structure that can be referred to instead of the IUPAC name. Consider bis{[(\(\mu\)-2-mercaptoethyl)(2-mercaptoethyl)-methylthioethylaminato (2-)]Nickel(II)}. Which is easier, to expect readers and hearers to work out the structure from that name or to just refer them to compound 42 in Figure \(\PageIndex{1}\)?

Figure \(\PageIndex{1}\). Structure of bis{[(\(\mu\)-2-mercaptoethyl)(2-mercaptoethyl)-methylthioethylaminato (2-)]Nickel(II)}. The authors of the synthesis of this compound in Inorganic syntheses1 may have had to figure out an IUPAC name for this compound but if you have this scheme in your paper and your instructor is OK with it you can just call it 42  

Rules for Naming Coordination Compounds

According to the Lewis base theory, ligands are Lewis bases since they can donate electrons to the central metal atom. The metals, in turn, are Lewis acids since they accept electrons. Coordination complexes consist of a ligand and a metal center cation. The overall charge can be positive, negative, or neutral. Coordination compounds are complex or contain complex ions. A ligand can be an anion or a neutral molecule that donates an electron pair to the complex (NH₃, H₂O, Cl^-). The number of ligands that attach to a metal depends on whether the ligand is monodentate or polydentate.

The name of a coordination compound communicates:

• information about isomerism, as appropriate
• how ligands are linked to the metal
• the identity of the metal and its oxidation state
• any counterions present

Rule 1: If ions are present, name the cation first, followed by the anion.

Example \(\PageIndex{1}\)

Name the following transition metal complexes.

1. K₂[PtCl₄]
2. [Co(NH₃)₆](NO₃)₃
3. [Co(NH₃)₆][Cr(C₂O₄)₃]

Solution

1. potassium tetrachloroplatinate(II)
2. hexaamminecobalt(III) nitrate
3. hexaamminecobalt(III) tris(oxolato)chromium(III)

Rule 2: When multiple isomers are possible, designate the particular isomer in italics at the front of the name of each complex

When a complex might exist as one of two stereoisomers, prefixes are commonly used to designate which isomer is present. The most common cases are demonstrated in Figure \(\PageIndex{2}\).

Figure \(\PageIndex{2}\): Application of nomenclature rules for stereosimerism about a metal. (LibreText)

Rule 3: Identity the ligands present by listing them in alphabetical order by ligand name.

The ligands are written in alphabetical order by the ligand name only; symbols are not considered and prefixes do not count in determining alphabetical order.

Example \(\PageIndex{2}\)

Name the complex ion [Co(NH₃)₅Cl]²⁺.

Solution

pentamminechlorocobalt(II)

The ammine ligand is named before the chloro ligand because the order is alphabetical by the ligand name by virtue of which ammine comes before chloro.

Rule 3a: Anionic Ligands 

Ligands that act as anions which end in "-ide" are replaced with an ending "-o" (e.g., Chloride → Chloro). Anions ending with "-ite" and "-ate" are replaced with endings "-ito" and "-ato" respectively (e.g., Nitrite → Nitrito, Nitrate → Nitrato).

Table \(\PageIndex{1}\): Anionic Monodentate Ligands

Molecular Formula	Ligand Name	Molecular Formula	Ligand Name
F^-	Fluoro	OH^-	Hydroxo
Cl^-	Chloro	SO4^2^-	Sulfato
Br^-	Bromo	S2O3^2^-	Thiosulfato
I^-	Iodo	NO2^-	Nitrito-N-; Nitro
O^2-	Oxo	ONO^-	Nitrito-O-; Nitrito
CN^-	Cyano	SCN^-	Thiocyanato-S-; Thiocyanato
NC^-	Isocyano	NCS^-	Thiocyanato-N-; Isothiocyanato

Rule 3b: Neutral Ligands

Most neutral molecules that are ligands carry their normal name with a few caveats:

• Names that involve spaces should either be put in parentheses or the spaces should be eliminated (preferred)

Example: cis-dichlorobis(dimethyl sulfoxide)platinum(II) or cis-dichlorobis(dimethylsulfoxide)platinum(II)

• A few ligands are named differently than their parent molecules. The few exceptions are the first four on the chart: ammine, aqua, carbonyl, and nitrosyl.

Table \(\PageIndex{2}\): Select Neutral  Ligands.

Molecular Formula of Ligand	Ligand Name
NH3	Ammine
H2O	Aqua
CO	Carbonyl
CS	Thiocarbonyl
NO	Nitrosyl
CH3NH2	Methylamine
C5H5N	Pyridine
en	Ethylenediamine
ox^2^-	Oxalato
EDTA^4^-	Ethylenediaminetetraacetato

Note: Ammine is spelled with two m's when referring to a ligand. Amines are a class of organic nitrogen-containing compounds.

Rule 4: Ligand Multiplicity

The number of ligands present in the complex is indicated with the prefixes di, tri, etc. The exceptions are polydentates that have a prefix already in their name (en and EDTA^4- are the most common). When indicating how many of these are present in a coordination complex, put the ligand's name in parentheses and use bis (for two ligands), tris (for three ligands), and tetrakis (for four ligands). Prefixes always go before the ligand name; they are not taken into account when putting ligands in alphabetical order. Note that "mono" often is not used. For example, \(\ce{[FeCl(CO)2(NH3)3]^{2+}}\) would be called triamminedicarbonylchloroiron(III) ion. Remember that ligands are always listed before the metal is listed in the name.

Table \(\PageIndex{3}\). Prefixes used to specify the number of a given ligand present.

Number of Identical Ligands	Prefix for Monodentate Ligands	Prefix for Polydentate or Complex Ligands
2	di-	bis-
3	tri-	tris-
4	tetra-	tetrakis-
5	penta-	pentakis-
6	hexa-	hexakis-
7	hepta-	heptakis-
8	octa-	octakis-
9	nona-	nonakis-
10	deca-	decakis-

Figure \(\PageIndex{3}\): Example of the use of prefixes to specify the number of ligands of each type in a complex. (LibreText)

Example \(\PageIndex{3}\)

What is the name of this complex ion: \(\ce{[CrCl2(H2O)4]^{+}}\)?

Solution

Let's start by identifying the ligands. The ligands here are Cl and H₂O. Therefore, we will use the monodentate ligand names of "chloro" and "aqua". Alphabetically, aqua comes before chloro, so this will be their order in the complex's name. There are 4 aqua's and 2 chloro's, so we will add the number prefixes before the names. Since both are monodentate ligands, we will say "tetra[aqua]di[chloro]".

Now that the ligands are named, we will name the metal itself. The metal is Cr, which is chromium. Therefore, this coordination complex is called tetraaquadichlorochromium(III) ion. See the next section for an explanation of the (III).

Rule 5: Specify the identity of the metal

In neutral and cationic complexes the metal's name is used directly. In anionic complexes, -ate replaces -ium, -en, or –ese or adds to the metal name.

Example \(\PageIndex{1}\)

Name the following complexes:

1. [Ru(NH₃)₆]³⁺
2. MnCl₆^2-

Solution

1. hexammineruthenium(III)
2. hexachloromanganate(IV)

Note: In anionic complexes of some metals a Latin-derived name is used instead of the element's English name. These names are given in Table \(\PageIndex{4}\). The rest of the metals simply have -ate added to the end (cobaltate, nickelate, zincate, osmate, cadmate, platinate, mercurate, etc. Note that the -ate tends to replace -um or -ium, if present).

Table \(\PageIndex{4}\). Latin terms for select metal ions.

Transition Metal	Latin
Copper	Cuprate
Gold	Aurate
Iron	Ferrate
Lead	Plumbate
Silver	Argentate
Tin	Stannate

Figure \(\PageIndex{4}\): Example of the application of the metal specification rules to a cationic and an anionic platinum complex.(LibreText)

Rule 6: Specify the oxidation state of the metal.

When naming the metal center, you must know the formal metal name and the oxidation state. To show the oxidation state, we use Roman numerals inside parenthesis.

Example \(\PageIndex{1}\)

Name the following complexes:

1. [CoCl(NH₃)₅]Cl₂
2. [PtBr₂(bpy)]
3. K[Ag(SCN)₂]

Solution

1. pentamminechlorocobalt(III) chloride
2. dibromobipyridineplatinium(II)
3. potassium di-S-thiocyanatoargentate(I)

Summary of rules for naming coordination complexes.

A graphical summary of the rules for naming complexes along with a few examples that you can use to review the nomenclature rules is given in Figure \(\PageIndex{5}\).

Figure \(PageIndex{5}\). Summary of nomenclature rules for coordination complexes along with a few examples of their application. 

This work by Stephen Contakes is licensed under a Creative Commons Attribution 4.0 International License.

Additional Examples

Example \(\PageIndex{2}\)

What is the name of [Cr(OH)₄]^- ?

Solution

Immediately we know that this complex is an anion. There is only one monodentate ligand, hydroxide. There are four of them, so we will use the name "tetrahydroxo". The metal is chromium, but since the complex is an anion, we will have to use the "-ate" ending, yielding "chromate". The oxidation state of the metal is 3 (x+(-1)4=-1). Write this with Roman numerals and parentheses (III) and place it after the metal to get tetrahydroxochromate(III) ion.

Example \(\PageIndex{3}\)

What is the name of \([\ce{Pt(NH3)4}][\ce{Pt(Cl)4}]\)?

Solution

NH₃ is neutral, making the first complex positively charged overall. Cl has a -1 charge, making the second complex the anion. Therefore, you will write the complex with NH₃ first, followed by the one with Cl (the same order as the formula). This coordination compound is called tetraammineplatinum(II) tetrachloroplatinate(II).

Writing Formulas of Coordination Complexes

While chemistry typically follow the nomenclature rules for naming complexes and compounds, there is disagreement with the rules for constructing formulas of inorganic complex. The order of ligand names in their formula has been ambiguous with different conventions being used (charged vs neutral, number of each ligand, etc.). In 2005, IUPAC adopted the recommendation that all ligand names in formulas be listed alphabetically (in the same way as in the naming convention) irrespective of the charge or number of each ligand type.

The rules as given here are adapted from a summary by Robert Lancashire.

1. If there are multiple ions present list the cations before anions.
2. Enclose all the constituents of each complex ion in square brackets.
3. For each complex ion,
   • Give the central metal atom first.
   • Then ligands next, listed in alphabetical order, ignoring prefixes according to the first letters in the ligand's symbol as written. This is true regardless of whether the symbol is an element symbol (like C, N, O, etc.) or a symbol for the ligand name (bpy, en, MeCN, etc.). Contrary to widely-circulated myths, the ligand's charge does not matter.⁴
   • The formulae or abbreviations (e.g. en) for all polyatomic ligands should be enclosed in ordinary parentheses.
   • As appropriate, use italicized atom symbols to indicate linkage isomerism and prefixes such as cis-, trans-, fac-, mer-, \(\Lambda\)-, \(\Delta\)-, κⁿ, ηⁿ , μ_n, \(\lambda\)-, or \(\delta\)- to indicate stereochemistry.
   • When a ligand is bound to a metal through a particular atom, preferably place that atom closest to the metal - e.g., [Fe(CN)₆]^3- not [Fe(NC)₆]^3- (Note: this rule is used primarily for ambidentate ligands; although IUPAC recommends that aqua ligands be written as OH₂ when the O would be closest to its coordinated metal, they are still usually written as H₂O).

Figure \(\PageIndex{6}\). Summary of the rules for writing the formula of a coordination complexes along with a few examples of their application. This work by Stephen Contakes is licensed under a Creative Commons Attribution 4.0 International License.

Examples \(\PageIndex{4}\)

Write the chemical formulas for:

1. Amminetetraaquachromium(II) ion
2. Amminesulfatochromium(II)

Solution

1. Amminetetraaquachromium(II) ion could be written as \(\ce{[Cr(H2O)4(NH3)]^{+2}}\) or \(\ce{[Cr(NH3)(H2O)4]^{+2}}\).
2. Amminesulfatochromium (II) could be written as \(\ce{[Cr(SO4)(NH3)]}\) or \(\ce{[Cr(NH3)(SO4)]}\).

Problems

Exercise \(\PageIndex{1}\)

What is the name of this complex ion: \(\ce{[CoCl_2(en)_2]^{+}}\)?

Answer

We take the same approach. There are two chloro and ethylenediamine ligands. The metal is Co, cobalt. We follow the same steps, except that \(en\) is a polydentate ligand with a prefix in its name (ethylenediamine), so "bis" is used instead of "di", and parentheses are added. Therefore, this coordination complex is called dichlorobis(ethylenediamine)cobalt(III) ion.

Exercise \(\PageIndex{2}\)

What is the name of \(\ce{[CuCl4]^{2-}}\)?

Answer

tetrachlorocuprate(II) ion

Exercise \(\PageIndex{3}\): The Nitro/Nitrito Ambidentate Ligand

What is the name of \(\ce{[CoCl(NO2)(NH3)4]^{+}}\) ?

Answer

This coordination complex is called tetraamminechloronitrito-N-cobalt(III). N comes before the O in the symbol for the nitrite ligand, so it is called nitrito-N. If an O came first, as in [CoCl(ONO)(NH₃)₄]⁺, the ligand would be called nitrito-O, yielding the name tetraamminechloronitrito-O-cobalt(III).

Nitro (for NO₂) and nitrito (for ONO) can also be used to describe the nitrite ligand, yielding the names tetraamminechloronitrocobalt(III) and tetraamminechloronitritocobalt(III).

Exercise \(\PageIndex{4}\): The Nitro/Nitrito Ambidentate Ligand

What is the name of \(\ce{[CoCl(NO2)(NH3)4]^{+}}\) ?

Answer

This coordination complex is called tetraamminechloronitrito-N-cobalt(III). N comes before the O in the symbol for the nitrite ligand, so it is called nitrito-N. If an O came first, as in [CoCl(ONO)(NH₃)₄]⁺, the ligand would be called nitrito-O, yielding the name tetraamminechloronitrito-O-cobalt(III).

Nitro (for NO₂) and nitrito (for ONO) can also be used to describe the nitrite ligand, yielding the names tetraamminechloronitrocobalt(III) and tetraamminechloronitritocobalt(III).

Exercise \(\PageIndex{5}\)

Write the chemical formulas for

1. Amminetetraaquachromium (II) sulfate
2. Potassium hexacyanoferrate (III)

Answer

1. Amminetetraaquachromium (II) sulfate can be written as \(\ce{[Cr(H2O)4(NH3)]SO4}\). Although \(\ce{[Cr(NH3)(H2O)4]SO4}\) is also acceptable.
2. Potassium hexacyanoferrate (III) is be written as \(\ce{K3[Fe(CN)6]}\)

Exercise \(\PageIndex{6}\). Assigning metal oxidation states in a complex

In order to name a complex it is necessary to assign a formal oxidation state to the metal. For this reason it is important to be able to assign the oxidation state of a metal in a complex. Fortunately, this is easy to do if you remember

1. The sum of all atoms' oxidation states will equal the overall charge on the complex
2. When determining the metal's oxidation state the ligands can be treated as having an oxidation state equal to their charge - i.e., the charge they possess in the form in which they coordinate the metal, so if they need to lose a proton to bind, don't forget to account for that.

Given the above, assign the oxidation state of the metal in the following real and hypothetical complexes.

1. K₃[Fe(CN)₆]
2. [CoCl(NH₃)₅](NO₃)₂
3. K₂[PtCl₄]
4. [MnCl(por)]
5. [Ru(bpy)₃]Cl₂
6. [PdCl₂(dppe)]
7. [Mn(en)₂(SCN)₂]

Answer for K₃[Fe(CN)₆]^3-.

This contains [Fe(CN)₆]^3-; so O.S._Fe + 6 x (-1) (for CN^-) = -3 (the complex's charge) so O.S._Fe = +3 or Fe³⁺.

Answer for [CoCl(NH₃)₅](NO₃)₂.

This contains [CoCl(NH₃)₅]²⁺; so O.S._Co + 1 x (-1) (for Cl^-) + 0 x 5 (for NH₃) = +2 (the complex's charge) so O.S._Co = +3 or Co³⁺.

Answer for K₂[PtCl₄].

This contains 2K⁺ and [PtCl₄]^2-; so O.S._Pt + 4 x (-1) (for Cl^-) = -2 (the complex's charge) so O.S._Pt = +2 or Pt²⁺.

Answer for [MnCl(por)].

O.S._Pt + 1 x (-2) (for por; see table 9.2.2) + 1 x (-1) (for Cl^-) = +0 (the complex's charge) so O.S._Mn = +3 or Mn³⁺.

Answer [Ru(bpy)₃]Cl₂.

The complex is [Ru(bpy)3]²⁺ so O.S._Ru + 0 x 3 (for bpy) = +2 (the complex's charge) so O.S._Ru = +2 or Ru²⁺.

Answer [PdCl₂(dppe)].

O.S._Pd + 2 x (-1) (for Cl^-) + 0 x 3 (for dppe) = +0 (the complex's charge) so O.S._Pd = +2 or Pd²⁺.

Answer [Mn(en)₂(SCN)₂].

O.S._Mn + (2 x 0) (for en) + 2 x (-1) (for SCN^-) = +0 (the complex's charge) so O.S._Mn = +2 or Mn²⁺.

Exercise \(\PageIndex{7}\): Simple Nomenclature Problems.

Name the following compounds:

1. [Ru(NH₃)₆](NO₃)₃
2. K₂[PtCl₄]
3. K[Ag(CN)₂]
4. Cs[CuBrCl₂F]
5. [Cu(acac)₂]

Answer

	Complex	Name
a	[Ru(NH3)6](NO3)3	hexammineruthenium(III) nitrate
b	K2[PtCl4]	potassium tetrachloroplatinate(II)
c	K[Ag(CN)2]	potassium dicyanoargentate(I)
d	Cs2[CuBrCl2F]	cesium bromodichlorofluorocuprate(II)
e	[Cu(acac)2]	bis(acetylacetonato)copper(II)

Exercise \(\PageIndex{8}\): More simple nomenclature problems.

Name the following compounds and ions.

1. Cu(OH)₄^-
2. [AuXe₄]²⁺
3. AuCl₄^-
4. Fe(CN)₆^3-
5. K₄[Fe(CN)₆]
6. trans-[Cu(en)₂(NO₂)₂] (the N is bound to Cu)
7. cis-IrCl₂(CO)(PPh₃) (ignore stereochemistry)
8. IrCl(PPh₃)₃

Answer

	Compound	Name
a	Cu(OH)4^-	tetrahydroxidocuprate(III) or tetrahydroxidocuprate(III)
b	[AuXe4]^2+	tetraxenongold(II)
c	AuCl4^-	tetrachloroaurate(III)
d	Fe(CN)6^3-	hexacyanoferrate(III) or hexacyanidoferrrate(III)
e	K4[Fe(CN)6]	potassium hexacyanoferrate(II) or potassium hexacyanidoferrrate(II)
f	trans-[Cu(en)2(NO2)2] (the N is bound to Cu)	bis(ethylenediamine)bisnitrocopper(II) or bis(ethylenediamine)bis(nitrito-\(\kappa\)N)copper(II)
g	cis-IrCl2(CO)(PPh3)	cis-dichlorocarbonyltriphenylphosphineiridium(I) or cis-dichloro(carbonyl)(triphenylphosphine)iridium(I)
h	IrCl(PPh3)3	chlorotris(triphenylphosphine)iridium(I)

Exercise \(\PageIndex{9}\): Even more simple nomenclature problems.

Name the following compounds and ions.

1. Fe(acac)₃
2. K₂[CuBr₄]
3. ReH₉
4. [Ag(NH_­3)₂]BF₄
5. [Ag(NH_­3)₂][Ag(CN)₂]
6. [Ni(CN)₄]^2-
7. [Co(N₃)(NH_­3)₅]SO₄
8. [CoBrCl(H₂O)(NH₃)]I (ignore stereochemistry)

Sample Answers

	Complex	Name
a	Fe(acac)3	tris(acetoacetato)iron(III)
b	Na2[CuBr4]	sodium tetrabromocuprate(II)
c	[Co(NH3)6][Co(ox)3]	hexamminecobalt(III) tris(oxalato)cobalt(III)
d	[Ag(NH­3)2]BF4	diamminesilver(I) tetrafluoroborate
e	[Ag(NH­3)2][Ag(CN)2]	diamminesilver(I) dicyanoargentate(I) or diamminesilver(I) dicyanidoargentate(I)
f	[Ni(CN)4]^2-	tetracyanonickelate(II) or tetracyanonickelate(II) ion
g	[Co(N3)(NH­3)5]SO4	pentammineazidocobalt(III) sulfate
h	[CoBrCl(H2O)(NH3)]I (ignore stereochemistry)	ammineaquabromochlorocobalt(III) iodide

Exercise \(\PageIndex{10}\): Nomenclature problems, some of which involve consideration of isomerism.

Name the following compounds and ions. Include the appropriate prefixes for designating isomers.

1. trans-[Cu(dppe)₂(NO₂)₂] (the N is bound to Cu)
2. [Pd(en)₂(SCN)₂], with the thiocyanates bound Pd-SCN
3. [Mn(CO)₆]BPh₄ (BPh₄ = tetraphenylborate)
4. Rb[AgF₄]
5. K₂ReH₉
6. K₃CrCl₆
7. [Ru(H₂O)₆]Cl₂
8. [cis-Fe(CO)₄I₂]
9. K₂[trans-Fe(CN)₄(CO)₂]
10. [cis-MnCl(H₂O)₄(NH₃)](NO₃)
11. K₃[fac-RuCl₃(PMe₃)₃]

Answer

	Complex	Name
a	trans-[Cu(dppe)2(NO2)2]	trans-bis(diphenylphosphinoethane)bisnitrocopper(II) or trans-bis(diphenylphosphinoethane)bis(nitrito-\(\kappa\)N)copper(II)
b	[Pd(en)2(SCN)2], with the thiocyanates bound Pd-SCN	bis(ethylenediamine)bisthiocyanatopalladium(II) or bis(ethylenediamine)bis(thiocyanato-S)palladium(II) or bis(ethylenediamine)bis(thiocyanato-\(\kappa\)S)palladium(II)
c	[Mn(CO)6]BPh4	hexacarbonylmanganese(I) tetraphenylborate
d	Rb[AgF4]	rubidium tetrafluoroargentate(III)
e	K2ReH9	potassium nonahydridorhenium(VII)
f	K3CrCl6 or K3[CrCl6]	potassium hexachlorochromium(III) or potassium hexachloridochromium(III)
g	[Ru(H2O)6]Cl2	hexaaquaruthenium(II) chloride
h	[cis-Fe(CO)4I2]	cis-tetracarbonyldiiodoiron(II)
i	K2[trans-Fe(CN)4(CO)2]	potassium trans-dicarbonyltetracyanoferrate(II)
j	[cis-MnCl(H2O)4(NH3)](NO3)	cis-amminetetraaquachloromanganese(0) nitrate
k	K[fac-RuCl3(PMe3)3]	potassium fac-trichlorotris(triphenylphosphine)ruthenium(II)

Exercise \(\PageIndex{11}\)

Name the compounds and ions. Include the appropriate prefixes for designating isomers.

Answer

#	Structure	Name
1		cis-tetraacetonitriledicyanoiron(II) or cis-tetraacetonitriledicyanidoiron(II)
2		trans-tetraacetonitriledicyanoiron(II) or trans-tetraacetonitriledicyanidoiron(II)
3		trans-bromochlorobis(ethylenediamine)iron(III) or trans-bromidochloridobis(ethylenediamine)iron(III)
4		fac-tricarbonyltricyanomolybdate(0) or fac-tricarbonyltricyanidomolybdate(0)
5		mer-tricarbonyltricyanomolybdate(0) or mer-tricarbonyltricyanidomolybdate(0)
6		pentamminenitrito-N-cobalt(III), pentamminenitrito-\(\kappa\)N-cobalt(III), or pentamminenitrocobalt(III)
7		pentamminenitrito-O-cobalt(2+), pentamminenitrito-\(\kappa\)O-cobalt(2+), or pentamminenitritocobalt(2+)

Exercise \(\PageIndex{12}\)

Draw structural formulae for the following compounds and ions. You may assume that

• complexes in which the metal has a coordination number of six are octahedral
• complexes in which the metal has a coordination number of five are trigonal bipyramidal
• complexes in which Pt^II , Pd^II , or Rh^I, or Ir^I have a coordination number of four are square planar
• other complexes in which the metal has a coordination number of four will be tetrahedral

1. (2,2'-bipyridine)tetracyanoruthenium(2-)
2. sodium tetrachloroaluminate (note that since Al is a main group metal with a generally fixed oxidation state no oxidation state is given)
3. pentaamminechlorocobalt(2+) sulfate
4. carbonylhydridotris(triphenylphosphine)rhodium(I) (the ligands in this complex occupy sterically preferred positions)
5. bromotrichlorocobaltate(III)
6. hexaaquacopper(2+) sulfate
7. sodium tris(oxalato)cobalt(III)
8. fac-(1,10-phenanthroline)tricarbonylchlororhenium(I)
9. mer-triaquatrichlorochromium(III)
10. trans-dichlorobis(ethylenediamine)platinum(IV)

Answers

a

b

 

c

 

d

 

e

 

f

 

g

h

i

j

 

Exercise \(\PageIndex{13}\).

The name of the structure named tris(tetraammine-\(\mu\)-dihydroxocobalt)cobalt(6+) in the figure below is incomplete. Give the complete name of the structure.

Answer

\(\Delta\)-tris(tetraammine-\(\mu\)-dihydroxocobalt(III)cobalt(III)

Exercise \(\PageIndex{14}\)

Give the formulae of the following complexes.

.

Answer

Exercise \(\PageIndex{15}\)

Write formulae for each of the following compounds and ions. When multidentate ligands are present use suitable abbreviations.

1. pentaamminechlorocobalt(2+) sulfate
2. \(\Delta\)-diamminebis(oxalato)manganate(III)
3. trans-tetraacetonitriledicyanoiron(II)
4. tricarbonyldichlorobis(triphenylphosphine)molybdenum

Answers

a.

[CoCl(NH₃)₅](SO₄)

b.

\(\Delta\)-[Mn(NH₃)₂(ox)₂]^-

c.

trans-[Fe(CN)₂(NCMe)₄]

d.

[MoCl₂(CO)₃(PPh₃)] or MoCl₂(CO)₃(PPh₃)

 

e.

mer-[CrBrCl(H₂O)₃I]

 

f.

[Co(O₂)py(salen)]

 

g.

[Fe(NO)₂(SEt)₂]^-

h.

[MnCl(por)]^- or [MnCl(porphyrin)]^-

 

i.

[Ni(DMG)₂] or [Ni(Hdmg)₂]

j.

potassium trans-[Fe(CN)₂(CO)₄]

k.

trans-[CuCl(H₂O)₄(NH₃)]SO₄

l.

trans-[PtCl₂(en)₂]²⁺

m.

cis-[CoBrCl(NH₃)₄]SO₄

n.

K₂[Fe(CN)₅NO]

Contributors and Attributions

• Justin Hosung Lee (UCD), Sophia Muller (UCD)