IUPAC NOMENCLATURE OF COORDINATION COMPOUNDS PDF

Coordination complexes have their own classes of isomers , different magnetic properties and colors , and various applications photography, cancer treatment, etc , so it makes sense that they would have a naming system as well. 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, for example:.

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Coordination complexes have their own classes of isomers , different magnetic properties and colors , and various applications photography, cancer treatment, etc , so it makes sense that they would have a naming system as well.

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, for example:. A ligand can be an anion or a neutral molecule that donates an electron pair to the complex NH 3 , H 2 O, Cl -.

The number of ligands that attach to a metal depends on whether the ligand is monodentate, bidentate, or polydentate. For more information, see Ligands and Chelation. To begin naming coordination complexes, here are some things to keep in mind. Ligands that act as anions which end in "-ide" are replaced with an ending "-o" e.

Anions ending with "-ite" and "-ate" are replaced with endings "-ito" and "-ato" respectively e. Most neutral molecules that are ligands carry their normal name. The few exceptions are the first four on the chart: ammine, aqua, carbonyl, and nitrosyl. 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 , tris , and tetrakis.

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.

Remember that ligands are always named first , before the metal is. Let's start by identifying the ligands. The ligands here are Cl and H 2 O. 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. We take the same approach.

There are two chloro and ethylenediamine ligands. The metal is Co, cobalt. Therefore, this coordination complex is called dichlorobis ethylenediamine cobalt III ion. 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. If the overall coordination complex is an anion, the ending "-ate" is attached to the metal center.

Some metals also change to their Latin names in this situation. The following change to their Latin names when part of an anion complex:. 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. Finally, when a complex has an overall charge, "ion" is written after it. Here are some examples with determining oxidation states, naming a metal in an anion complex, and naming coordination compounds.

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".

A last little side note: when naming a coordination compound, it is important that you name the cation first, then the anion. You base this on the charge of the ligand. Think of NaCl. Na, the positive cation, comes first and Cl, the negative anion, follows.

NH 3 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 NH 3 first, followed by the one with Cl the same order as the formula. This coordination compound is called tetraammineplatinum II tetrachloroplatinate II. 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. The formula of a coordination complex is written in a different order than its name. The chemical symbol of the metal center is written first. The ligands are written next, with anion ligands coming before neutral ligands. If there is more than one anion or neutral ligand, they are written in alphabetical order according to the first letter in their chemical formula. In a coordination compound's name, when one of the ions is just an element, the number of atoms is not indicated with a prefix.

Since it still has to be written in the formula, it is determined by balancing the overall charge of the compound. Learning Objectives To learn the basis for complex ion and compound nomenclature. Introduction According to the Lewis base theory , ligands are Lewis bases since they can donate electrons to the central metal atom.

Ligands are named first in alphabetical order. The name of the metal comes next. Rule 1: Anionic Ligands Ligands that act as anions which end in "-ide" are replaced with an ending "-o" e. Rule 2: Neutral Ligands Most neutral molecules that are ligands carry their normal name. Note: Ammine is spelled with two m's when referring to a ligand.

Amines are a class of organic nitrogen-containing compounds. Rule 3: Ligand Multiplicity The number of ligands present in the complex is indicated with the prefixes di, tri, etc. Number of Ligands Monodentate Ligands Polydentate Ligands 1 mono - 2 di bis 3 tri tris 4 tetra tetrakis 5 penta - 6 hexa - Prefixes always go before the ligand name; they are not taken into account when putting ligands in alphabetical order. Solution Let's start by identifying the ligands. Solution We take the same approach.

Rule 4: The Metals When naming the metal center, you must know the formal metal name and the oxidation state. Solution Immediately we know that this complex is an anion. Solution tetrachlorocuprate II ion. Solution NH 3 is neutral, making the first complex positively charged overall. Distinguishing between linkage isomers. Writing Formulas of Coordination Complexes The formula of a coordination complex is written in a different order than its name.

Both ligands are neutral, so they are ordered alphabetically with H 2 O before NH 3. Their order in the formula is the opposite of that in the complex's name since one uses their chemical symbols and the other uses the names of the ligands. SO 4 is an anion, so it comes before NH 3. If you did, you are correct.

Remember to balance the K! References Petrucci, Ralph H. General Chemistry Principles and Modern Applications.

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Coordination complex

Many transition metals exist as more than one type of cation. Therefore, when you are naming an ionic compound containing iron, it is necessary to indicate which oxidation number the metal has. The oxidation number appears as a Roman numeral in parenthesis after the cation. For metals, the oxidation number is the same as the charge. The procedure for naming ionic compounds containing polyatomic ions is the same as that for naming simple ions. Example 1: Write a correct chemical formula for each of the following ionic compounds: a.

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Coordination Compounds: Nomenclature & Properties

Saranya has a masters degree in Chemistry and in Secondary Education. She has taught high school, AP chemistry for 2 years and is teaching undergraduate college chemistry for 3 years. Log in or sign up to add this lesson to a Custom Course. Log in or Sign up. There are some specific rules for naming coordination compounds. Following are the main rules for naming coordination compounds according to the IUPAC recommendations of

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Nomenclature of Coordination Complexes

A complex is a substance in which a metal atom or ion is associated with a group of neutral molecules or anions called ligands. Coordination compounds are neutral substances i. You will learn more about coordination compounds in the lab lectures of experiment 4 in this course. The coordination compounds are named in the following way.

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