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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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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32 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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60 views

Transition metal complex question

I am given a blue solid W and it contains a tetraammine copper(II) complex and a ${SO_4}^{2-}$ . I added dilute sulphuric acid until the solution is pale blue; then added potassium iodide solution. A ...
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66 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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76 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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63 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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49 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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104 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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53 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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69 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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26 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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449 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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52 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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173 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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73 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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152 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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56 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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62 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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64 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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98 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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191 views

Co-ordination compound [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 $[Co(SCN)4]^{2-}$ . Since SCN is a weak ligand I did not pair the electrons but ...
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100 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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3k views

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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187 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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496 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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104 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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413 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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916 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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110 views

IR absorbance on [Co(NH3)5(H2O)]2+

Does anyone know where can I find something like a table or any kind of database for IR spectra in inorganic compounds? I need to describe this compound for a lab report but can't find anything in ...
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168 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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234 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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905 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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81 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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175 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 ...
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191 views

Bonding in a bridged metal carbonyl

Can someone please explain the bonding in a bridged metal carbonyl (like diiron nonacarbonyl)? I cannot understand what kind of bonds (sigma/pi) exist between the bridging carbonyls and the metals. ...
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253 views

What does the eta notation mean in the naming of a transition metal complex?

I am reading a paper (Gutel et al., J. Mater. Chem. 2007, 17, 3290-3292) and I have come across the following reaction: In organic solvents, the decomposition under mild conditions of ...
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2k views

Why do transition elements make colored compounds?

Why do transition metals element make colored compound both in solid form and in solution? Is it related with their electrons or something else?
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4k views

Tetrahedral or Square Planar

How can one predict whether a given complex ion will be square planar or tetrahedral when its coordination number is 4 using crystal field theory ? Is it possible to theoretically predict this?
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1k views

Normal Spinel and Inverse Spinel

According to my notes, [OCTAHEDRAL SITE STABILIZATION ENERGY (OSSE)], sterical effects and electronic effects in stability create a confusion in this theory. However, we are able to solve this problem ...
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983 views

Complexes formed by Lanthanides and Actinides

A very simple test for the presence of alcohols in the lab involves adding Ceric(IV) Ammonium Nitrate solution which gives a pinkish red colour in the presence of alcohol. When I looked up the ...
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383 views

What is the meaning of '(en)'?

What is the meaning of $ (en) $ on this two coordination compounds: $[Co(en)_2(NO_2)_2]Cl$ $[Cd(en)_2(CN)_2]$ Is it a type of compound? If yes, what is the meaning?
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450 views

MO-Scheme of SCN- and its bonding properties when used as a ligand

I tried to figure out the MO-scheme of the tetragonal-bipyramidal complex trans-$\ce{[Co(en)2(NCS)2]SCN}$ in which the isothiocyanate ligands are bound to the $\ce{Co^3+}$-Ion in $\eta^{1}$-mode (en = ...
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How do copper sulphate and the like change crystal structure on adding water of hydration?

Copper sulphate, in its hydrated form, is crystalline, whereas the anhydrous form is amorphous. Gypsum has a similar story-- on heating the crystalline dihydrate we get an amorphous hemihydrate. ...
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104 views

What are the mechanisms for capture of As(III) and As(V) by magnetite from water?

Magnetite, $\ce{Fe3O4}$ is able to capture $\ce{As(III)}$ and $\ce{As(V)}$ from drinking water through the following mechanisms. Bidentate-binuclear complex Monodentate-binuclear complex ...
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80 views

How to understand this form of writing the solution: (some salt • n H₂O)?

For example — "high purity chloride salt of Zinc (ZnCl₂ . 2 H₂O)" or "various concentrations of FeCl₂ . 4 H₂O". What does the number before H₂O mean?
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Why is iron in the brown ring compound in a +1 oxidation state?

In the standard brown ring test for the nitrate ion, the brown ring is $$\ce{[Fe(H2O)5 (NO)]^{2+}}$$ In this compound, the nitrosyl ligand is positively charged, and iron is in a $+1$ oxidation ...
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182 views

Why does benzene bend in this reaction?

From here I can see why hapticity changes here, but not why it is necessary for the benzene ring to bend. The resonance energy of benzene is pretty large, and there's no balancing increase in ...
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158 views

Is aqueous medium necessary for complex formation? if so, why?

If dry ammonia gas is passed through anhydrous copper sulfate, will it turn blue (due to the formation of tetraamminecopper(II) complex)? Or will silver chloride form diamminesilver(I) complex in ...
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774 views

How may copper acetate ligands be manipulated to change colors?

I have a solution of copper acetate and I would like to play around with the ligands to get different colors. Background: The copper acetate was made through mixing vinegar (5% acetic acid), NaCl, ...