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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Bipyridyl complex isomers

What type of stereoisomers do these two complex compounds represent?
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Why is inner orbital complex more stable than outer orbital complex?

I learnt that $\ce{Cr(II)}$ ion is a stronger reducing agent than $\ce{Fe(II)}$ In an aqueous solution as inner orbital complexes more stable than outer orbital complexes? I cannot understand why is ...
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Are there ways to fully dissociate a complex salt?

A complex salt is a salt where the metal and ligands do not dissociate in water. For eg : $\space\ce{K_4[Fe(CN)_6]}$ when put into $\space\ce{H_2O}$ dissociates as : $\space\ce{4K^+} + ...
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Why do electrons not get paired up in [Fe(H2O)5NO]2+?

The magnetic moment of [Fe(H2O)5NO]2+ is 3.87 Bohr magneton, which implies there are 3 unpaired electrons. Since iron is in +1 oxidation state (due to charge transfer with nitrosyl group), it's ...
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30 views

MO scheme for coordination complexes (tetrahedral) - Heteroligand vs. homoligand

How is the MO diagram drawn for a tetrahedral complex with heteroligands (e.g. $\ce{[NiCl2(PPh3)2]}$) different from a tetrahedral complex with the same type of ligand? Do we consider the same "a1 and ...
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Why is copper (II) coordination number so big?

Consider tetraaminecopper (II) ion. $\ce{[Cu(NH3)4]++}$ or $\ce{[Cu(NH3)4(H2O)2]++}$ Copper (II) ion has electron configuration $\ce{[Ar] 3d^9}$. How do the 4 electron pairs from ammonia atoms form ...
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Effect of radioactivity on bonding [duplicate]

What effect does $\alpha$ or $\beta$ decay have on the bonding in molecules? In particular the example I was thinking of was if you have a radioactive metal at the centre of a complex ion. I had a ...
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126 views

Is tetraammine dichloro cobalt (III) an optically active compound?

Is $$ \text{Co}[{(\text{N}{\text{H}}_{3})}_{4}{\text{Cl}}_{2}]$$ optically active? If so, write its stereo-isomers. I know that for a compound to be optically active, it should ...
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64 views

Why would there be differences in UV/Vis spectrum?

$\ce{[NEt4]2[NiBr]}$ dissolved in $\ce{MeCN}$ and $\ce{[NEt4]2[NiBr]}$ dissolved in $\ce{H2O}$ have different UV/visible spectra in the visible region. How would they differ, for example would one of ...
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What is this compound that was made? [closed]

1.25g $\ce{Ni(en)2Cl2}$ in 10ml water + 2 drops of pyridine + 1g 2,4-pentanedione in 10ml $\ce{MeOH}$ refluxed for 2 hours, large crystals formed It is a $\ce{Ni(II)}$ square planar compound Mass ...
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Thermogravimetric Analysis of hydrated compounds

I have been given this thermogravimetric analysis of my compound $\ce{NiBr2.$x$\,H2O}$ and I need to work out the number of moles of water in the complex. Also why are there two steps in the data?
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What does it mean in a Ni(II)complex if the HNMR spectrum appears unbroadened and unshifted & what does this tell you about the coordination geometry?

I am trying to work out the an unknown Ni(II) complex. I don't known the geometry and I have read that broad lines on the nmr spectrum indicate large compounds with symmetric environments. Does this ...
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Why does Cobalt have different coordination numbers in its complexes with water and thiocyanate?

I'd like to know why does cobalt(II), $\ce{Co^2+}$, form $\ce{[Co(H2O)6]^2+}$ complex with water while it forms $\ce{[Co(SCN)4]^2-}$ with the thiocyanate? Why is there $\ce{6H2O}$ but only $\ce{4 ...
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3answers
130 views

Are these reaction equations for the formation of the brown ring complex correct?

The above are the reactions given in my book for the qualitative analysis of nitrate ion (formation of the brown ring complex). I think that the reactions above are incorrect. The first one shows ...
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1answer
176 views

How do I find the oxidation number of a coordination complex

I actually know how to calculate the oxidation number for coordination complexes but some complexes like the below are giving some reistance $\ce{[Cu(NH3)_2][Fe(H2O)_3]}$ (diamminecopper(?) ...
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Reference request- List of common Coordination Complexes? [on hold]

I'm studying for a big chemistry exam that always has a question about predicting reactions. One thing that almost always trips me up is coordination complexes. For example, one such question asked ...
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Why is nickel tetracyanonickelate square planar?

Why is nickel tetracyanonickelate, $\ce{[Ni(CN)4]^{2-}}$ square planar? CN, for being a strong field, would not follow Hückel's rule. the central atom $\ce{Ni}$ would have a +2 charge so its ...
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Magnetic moments of tetrahedral Cobalt (II) and (III) complexes

From the spin-only formula we can predict that for tetrahedral cobalt (II) complexes $$m_{eff} = 3.87 \mu_B $$ This ignores orbital angular momentum effects, which result in higher magnetic moments ...
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Cu2+ octahedral complexes

$\ce{Cu}^{2+}$ has nine d-electrons, regardless of the ligand field strength it will have one free electron (so it is paramagnetic. Are $\ce{Cu}^{2+}$ octahedral complexes high spin or low spin?
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Why are square planar coordination compounds with four different ligands optically inactive?

Why square planar co- ordination compounds of type Mabcd do not show optical activity, although they contain 4 different ligands ( i.e. chiral central metal atom)
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Which ligands would be exchanged in this reaction?

I have this reaction and need to state what the products would be: $\ce{(CF3)2PH + [W(CO)5(THF)] -> }$ THF stands for Tetrahydrofuran. Would this just be a simple ligand exchange, and if so ...
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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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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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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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339 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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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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67 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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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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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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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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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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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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Inorganic chemistry reaction mechanisms

Are there well developed reaction mechanisms in inorganic chemistry like those in organic chemistry? If yes, please suggest an easy to follow reference.
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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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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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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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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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161 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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137 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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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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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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231 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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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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201 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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128 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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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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230 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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250 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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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 ...