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A special class of compounds in which a electron deficient central atom (usually a metal ion) is bonded to many electron donors called ligands. These compounds are highly stable and are widely found in nature. They also have a wide variety of industrial applications.

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Absorbtion of light by a Coordination Compound

A $\ce{[M(H2O)6]^{2+}}$ complex typically absorbs at around $600$ nm. It is allowed to form a new complex $\ce{[M(NH3)6]^{2+}}$ that should have absorbtion at? The absorbtion is beacuse of transition ...
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118 views

What are t2g and eg in CFT?

In the Crystal Field Theory, when the splitting of the d-orbital occurs, it gets divided into two parts... The upper part with higher Energy is the $t_{2g}$ and the lower part with lower Energy is ...
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238 views

Symmetry labels for orbitals

What are the symmetry labels for the p and d orbitals of $\ce {[PtCl4]^{2-}}$ ? I understand the concept of symmetry labels for molecules. some explanation of how it applies to orbitals would be ...
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147 views

Why are d-d electronic transitions forbidden and weakly absorbing? Why do they occur at all?

I am unable to understand why d-d electronic transitions are forbidden? Why are they weakly absorbing and apart from that, why do they occur at all?
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How many different possible structures (isomers) are there for the complex, [Mn(OH2)3(NH3)3] 3+?

How many different possible structures (isomers) are there for the complex, $\ce{[Mn(OH2)3(NH3)3]^{3+}}$? I really don't know how to begin with this. I know the answer is 2, but i don't have the ...
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110 views

Why does Co2+ have 7 electrons in the 3d orbital, and not 5 like Mn?

I'm taking general chemistry 2 this half of the summer. We are currently going over coordination complexes, ligands and transition metal ions. In particular, this question is in regards to the ligand ...
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46 views

How many ligands in Heme?

How many ligands does Fe has in heme ? I am not sure how many are in heme and how many in cytochrome C. Its about iron complexes.
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105 views

In the lattice model, what's a nearest neighbor?

I was reviewing my grad Thermodynamics textbook to go over a concept that I never learned well: the Lattice model. One set of equations1 has: $zN_1=2N_{11}+N_{12}$ $zN_2=2N_{22}+N_{12}$ where $z$ ...
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44 views

square planar geometry in metal complex

I don't understand what this statements wants to say, "Square planar geometry is favoured by ligands that can form pi bonds by accepting electrons from metal atoms or ions" How is this possible I ...
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63 views

What is the coordination number for BeCl2?

I am confused, should it be 2 or 4? If I consider $\ce{BeCl2}$ as a chain structure the coordination number is 4, and in the gas phase it is 2.
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43 views

Electride salt preparation

In preparation for the Birch reduction, I am trying to prepare an electride salt, [Na(NH3)6]+, e-. This salt should be brilliant blue, as far as I know, but I am getting a black sludge when adding ...
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59 views

Co(H₂O)₆ , a low spin coordination complex,why?

Despite $\ce{H2O}$ being a weak field ligand, why is $\ce{[Co(H2O)6]^3+}$ a low spin complex?
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33 views

Which d-block cation has the maximum hydration enthalpy?

Among $Mn^{2+}, V^{2+}, Ni^{2+},$ and $Ti^{2+},$ which cation is having the highest hydration energy to form the aqua complex $[M(H_2O)_6]^{2+}$ My approach: I guess $Mn^{2+}$ should be the answer as ...
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120 views

The bond in coordination complexes

This is a very basic question and I'm surprised it only just struck me. The nature of the bond in coordination complexes is a coordinate covalent bond. Only the ligand donates electrons for bond ...
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66 views

Heating CrCl3(Bipy)3 (undergraduate exam question)

CrCl3(Bipy)3 (A) when heated forms (B) which has the formula CrCl3(Bipy)2 and has one free Cl- per mole of (B) (Not given in question but i don't need help with the gravimetric analysis bit, just take ...
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146 views

How can the 18 electron rule be used to explain that Fe(η5-C5H5)2 doesn't react with hydrogen but Ni(η5-C5H5)2 does?

Fe(η5-C5H5)2 does not react with hydrogen, but its nickel analogue, Ni(η5-C5H5)2 is readily hydrogenated to give Ni(η5-C5H5)(η3-C5H7). Use the 18 electron rule to explain this behaviour. My answer so ...
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158 views

Structure of Fe1C13H10O2

The reaction of $\ce{(C5H5)Fe(CO)2Cl}$ with an equimolar amount of $\ce{Li+[C6H5]-}$ gives a product. Draw its structure and apply the 18 electron rule. In a question I was given the ...
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96 views

Zinc Picolinate - Positive, negative or neutral charge?

I'm going to be using a finings agent with a positive charge to remove negative trub from a solution (beer). I would like to keep some chelated zinc in the solution - ideally zinc picolinate - so ...
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1answer
64 views

Different coloured chromium salts

Evaporating cold aqueous chromium(III) chloride produces violet crystals. However when hot aqueous chromium(III) chloride crystallizes, green crystals result. Could someone please explain the ...
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333 views

What reaction takes place when potassium iodide is added to a tetraammine copper(II) complex?

I am given a blue solid W and it contains a tetraammine copper(II) complex and a $\ce{SO_4^{2-}}$ . I added dilute sulphuric acid until the solution is pale blue; then added potassium iodide solution. ...
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131 views

How is an aqueous Ag+ the same as [Ag(H2O)2]+?

$\ce{Ag^{+}_{(aq)}}$ can be written as $\ce{[Ag(H2O)2]+}$ but how would you know that it bonds with 2 water molecules? I don't get when ligands randomly form 6, 4, 2 bonds.
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142 views

What are the products of [Ti(H2O)6]Cl3 + H2SO4 + K2Cr2O7 --->

Im slightly lost on how to proceed with this equation. I know potassium dichromate is a strong oxidizing agent but im unsure of how to deal with it along with the titanium complex complex. Was ...
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131 views

Predicting bond-strength of metal carbonyls

The metal carbonyls (and similar organometallic compounds) involve a combination of sigma bond, a pi bond and backbonding. The bond strengths under consideration are the metal-carbon bond and the ...
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1answer
89 views

Ligand exchange reactions… are they one way or reversible?

Are ligand exchange reactions one-way reactions or reversible? I know this is a very silly question but its not said outright in any place... For example, in my high school chemistry book, these two ...
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231 views

Colours and transition metals

From my book: "When white light shines through a solution of a complex ion of a transition metal, photons of a particular frequency are absorbed and their energy promotes an electron from lower ...
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110 views

Splitting of $d$ orbitals when ligands approach central metal ion

In my high school chemistry book, it is written that when ligands approach the central metal ion (transition metal ion) to form dative bonds, the $3d$ orbitals split into two: two which are in higher ...
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1answer
174 views

How can different no. of unpaired electrons lead to different colours of co-ordination compounds?

To make the question clear I would like to take an example. $\ce{K_3[Fe(CN)6]}$ and $\ce{K3[FeF6]}$ shows different colors in solutions. It is given in my textbook that it is because of different ...
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1answer
40 views

Does deprotonation of a hexaaquaion continue until neutral charge

I learned that deprotonation is the process in which a proton is lost from ligand $\ce{H2O}$ molecules surrounding a central metal ion (I am referring to hexaaqua ions). Also, the process continues ...
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2k views

Werner's theory and complex salts

According to Werner's theory, metal ions have two types of valency-primary and secondary, where the primary valency is said to be satisfied by negative ions only, and the secondary valency can be ...
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1answer
60 views

Does chelation take ions out of solution

Does EDTA take $\ce{Mg^{2+}}$ and $\ce{Mn^{2+}}$ out of solution, so that it can be removed by a filter? Or does it just take it out of any chemical reactions going on in the solution?
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512 views

Potassium permanganate hybridisation

I'm clear with the concepts of crystal field theory. But I can't point out the exact reason why is the hybridisation of potassium permanganate ($\ce{KMnO4}$) is $d^3s$. Can anyone explain please?
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89 views

Which d-orbitals split according to CFT?

According to CFT, the degenerate d-orbitals split into $eg$ and $t_2 g$ groups. Are these the outermost nd orbitals which are vacant(4-d in case of 4th period) or the penultimate filled (n-1)d ...
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257 views

Why Cl- can't act as bidentate ligand?

Cl- is a monodentate ligand. It has four lone pairs then why it can't donate two lone pairs to central atom and act as a bidentate ligand?
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1answer
114 views

Difference between sodium ion and a transition metal ion dissolving in water?

In class, I learned that when $\ce {NaCl}$ is dissolved in water, the partially negative oxygen part of the water molecules surround the Na+ ion and energy is given off (hydration enthalpy) Likewise, ...
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1answer
92 views

Formation of coordination complexes?

I'm having trouble understanding how exactly coordination complexes are formed. Compounds such as $\ce{[Cu(H2O)6]++}$ are the ligands filled into the empty 3 of 4p orbitals+ 1 of 5s orbital + 2 of ...
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1answer
132 views

If I add some KOH, where will the reaction shifts?

I just got a final test and one of the question is: $\ce {Ni^2+}$ + 6$\ce{NH_3}$ $\ce {<=>}$ $\ce{[Ni(NH3)6]^2+}$ If we add some aqueous $\ce{KOH}$ after the reaction reach equilibrium, where ...
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150 views

Magnetic moment of coordination complexes?

To understand the commonly quoted magnetic values of coordination complexes (central ion) we use $$m_l=\sqrt{n(n+2)} \text{BM where BM}=\frac{e\hbar}{2m_e}\text{JT}^{-1}$$ $n$=number of unpaired ...
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240 views

What is the number of unpaired electrons in [Co(SCN)₄]²⁻?

Find the number of unpaired electrons present in the d orbital (whose lobes are present along the axis) for the complex $\ce{[Co(SCN)4]^{2-}}$. Since $\ce{SCN}$ is a weak ligand I did not pair ...
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1answer
164 views

Symmetry and stability of a molecule (Jahn-Teller Distortion)

I've taught in my class that if a molecule posses high degree of symmetry it's stability will be more,in other words symmetry and stability are directly proportional. Is this statement correct? And if ...
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How to calculate crystal field stabilisation energy?

How to calculate it? I know that it depends on the coordination compound and the number of electrons present in t2g and eg orbitals and the final answer is expressed in terms of crystal field ...
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1answer
410 views

Are there positive ligands?

Are there positive ligands which can bind to the central metal atom to form co-ordination compounds? $My$ $thoughts:$I know that ligands are Lewis bases which donate a pair of electrons and the ...
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1answer
1k views

Is there a mnemonic to study the spectrochemical series?

Mnemonics help to by-heart things which are difficult to do so and which are important. I found mnemonics for studying the periodic table, electromagnetic series etc which were of great help.So, is ...
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140 views

Oxidation state of metal in metal oxo complexes always positive?

Do all metals in metal oxo complexes (eg $\ce{Fe}$ in Ferrate, $\ce{Mo}$ in $\ce{MoO4}$,...) have positive oxidation states?
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1answer
905 views

Optical isomerism in Co-ordination Compounds

Optical isomerism in normal organic molecules can be found out my looking for chiral carbon and and the no. of isomers can be found out by drawing different spacial orientations of the same. But, I ...
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1k views

Difference between 18 electron rule and effective atomic number rule

Is there any difference between 18-electron rule and effective atomic number rule? Both rules are based on attainment of a noble gas configuraion as a criteria for stability of complexes. Besides, ...
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230 views

Geometrical Isomerism of Metal Complex

Does $\ce{Ni((en)2(Cl)2)}$ show cis-trans form ? And if No Why not ?
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304 views

What Could Formations of Linkage Isomers of [Co(NH3)NO2]^2+ be like ?

I am trying to draw the structure of this complex [Co(NH3)NO2]^2+ ,however I am not sure if the linkage isomers of this complex like this ;
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2k views

Total magnetic moment of atom

Whenever I read about coordination compounds in my textbooks, I always find a discussion about spin-only magnetic moment which is given by $\sqrt{n(n+2)}$ BM, Where $n$ is the number of unpaired ...
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1answer
101 views

Strongest chloride complex as perdicted by HSAB theory

Why won't $\ce{Ni^2+}$ form a complex with $\ce{Cl-}$, while the ions $\ce{Cu^2+}$ and $\ce{Co^2+}$ form the complexes $\ce{[CuCl4]^2-}$ and $\ce{[CoCl4]^2-}$? According to the HSAB theory, ...
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1answer
205 views

Which d-orbital configurations form an octahedral complex?

With reference to crystal field splitting in octahedral complexes, my textbook shows the following table of distribution of $d$-orbital electrons in octahedral complexes, based on the energy ...