Name the following coordination compounds. a. [Cr(H2 O)5 Br] Br2 c. [Fe(NH2 CH2 CH2 NH2)2(NO2)2]

Name the following coordination compounds. a. [Cr(H2 O)5 Br]...

Key Concepts

Coordination Compound Nomenclature

This concept involves the systematic rules used to name coordination compounds according to IUPAC guidelines. It covers the order in which ligands are named, the use of prefixes to denote the number of each type of ligand, and the proper naming of the central metal atom along with its oxidation state. Special conventions are applied based on whether the complex ion is neutral, cationic, or anionic.

Ligands and their Naming

In coordination chemistry, ligands are ions or molecules that donate electron pairs to the central metal atom. The names of ligands are determined by their identity and the way they bond to the metal, often using specific ligand names such as aqua for water or ammine for ammonia. When ligands are polydentate (binding through multiple sites) or ambidentate (capable of bonding in more than one way), additional modifiers or prefixes are used to reflect these bonding modes.

Oxidation State Determination

Determining the oxidation state of the central metal in a complex is essential for its proper naming. This involves accounting for the charges contributed by each ligand and any counter ions present. The oxidation state is indicated in the name by a Roman numeral in parentheses following the metal name, which helps in understanding the electronic structure and reactivity of the complex.

Counter Ions and Overall Charge

Coordination compounds often include counter ions that balance the overall charge of the complex ion. These counter ions are not part of the coordination sphere but are essential for the compound's neutrality. Distinguishing between the inner coordination sphere and the outer sphere of counter ions is crucial when naming the compound, as the nomenclature for the complex ion and the counter ions may follow different rules.

Ambidentate Ligands

Some ligands, known as ambidentate ligands, can coordinate to the metal center through more than one atom. A classic example is the nitrite ion, which can bind through either the nitrogen or oxygen atom. In such cases, specific naming conventions (such as using the kappa [?] notation or different names like nitro or nitrito) are employed to indicate the binding site, which is important in understanding the structure and properties of the complex.

Transcript

00:01 We have to name the coordination compounds here we have given c r h2o all 5 b r b r 2 so we have here to name the license first of all and then we will name the central metal atom or ion okay so now we have here two kind of license we have h2o and we have b r h2 o is named as aqua okay so we will follow the alphabetical order so h2 or 5 in number so prefix will be added here and for 5 we add the prefix penta so penta then aqua then we have br here so when it is br present inside the coordination sphere so it is named as bromo now we have chromium here so it is named as like chromium here as it is now we will write the oxidation number that oxidation number is written in the form of roman numeral so now br carries minus one charge and it is also present outside the coordination square they are two in number so overall there will be plus three oxidation state and it is named in the form of roman numeral as third and then we have bromide here okay when it is present outside the coordination sphere then in the case of halogens like chloride like we have chlorine bromine and we have chlorine okay so in that case of halogens we name them outside the coordination sphere after adding id okay so this will be named as bromide okay so this will be the name and here we will not leave any gap while writing the name now b part we have n -a -3 coordination sphere co cn whole 6 so i have metal present outside the coordination sphere whenever this happens whenever we have two different metal one metal is present outside the coordination sphere then that metal is named as it is so that is sodium okay then now i have this c lisen here okay so the lisons are to be named first they are in six so since they are six in number so the prefix hexa will use here so this will be hexas cyanido and now i have cobalt here so now see since i have n a 3 that is we have 3 sodium ions.

03:24 This means that we have 3 positive charge here, right? n .a carries positive charge.

03:29 So there will be 3 positive charge.

03:31 So i can see that here on this complex we have on this coordination square, we have 3 negative charge.

03:39 Okay.

03:40 So now this means for this reason, this metal present inside the coordination sphere, this is named after adding 8 suffix.

03:51 So this will be named as cobaltate.

03:57 Okay.

04:00 Now, oxidation number is written.

04:06 So, since it carries three negative charge and if i consider the oxidation state for cobalt bx, then there will be plus 6 minus 1.

04:17 For c and we have minus 1 charge.

04:19 That's equal to 3.

04:22 Okay.

04:23 So that is plus 3 for n .a.

04:25 Right so this will be equals to x is equals to mine this will be here six minus three right that's equal to three right so this the oxidation state is third here okay so now moving on to next part we have c part we have fc n h2 ch 2 c h 2 c h 2 nh2, old twice, no2, all twice, and cl is present outside the coordination experience.

05:21 So now in this case i have two kind of license.

05:24 I have this complex license here.

05:29 So that is actually ethylene diamine.

05:31 Okay...

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