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.

learn more… | top users | synonyms (2)

2
votes
0answers
21 views

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 ...
0
votes
0answers
19 views

How to determine the mole ratio of a given compound? [on hold]

A solution of $\ce{CuCl2.2H2O}$, $0.70~\mathrm{g}$, in hot water, $14.0~\mathrm{mL}$, is added to a boiling solution of 2,2’-bipyridine, $\ce{bipy}$, $1.50~\mathrm{g}$ in $40~\mathrm{mL}$ of ...
5
votes
2answers
111 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 ...
1
vote
1answer
50 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 ...
1
vote
0answers
48 views

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 ...
0
votes
2answers
40 views

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?
2
votes
1answer
84 views

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 ...
4
votes
2answers
76 views

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 ...
2
votes
3answers
99 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 ...
1
vote
1answer
81 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(?) ...
1
vote
0answers
39 views

List of common Coordination Complexes

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 ...
1
vote
1answer
64 views

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 ...
1
vote
1answer
52 views

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 ...
2
votes
1answer
50 views

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?
2
votes
1answer
38 views

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)
1
vote
1answer
31 views

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 ...
1
vote
0answers
21 views

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 ...
5
votes
1answer
1k 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 ...
4
votes
1answer
516 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 ...
4
votes
1answer
275 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?
3
votes
2answers
254 views

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 ...
2
votes
1answer
756 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 ...
1
vote
1answer
63 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.
3
votes
1answer
156 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 $z$ ...
0
votes
1answer
48 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 ...
0
votes
2answers
114 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.
2
votes
1answer
51 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 ...
1
vote
0answers
65 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?
5
votes
1answer
179 views

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.
0
votes
1answer
54 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 ...
4
votes
1answer
171 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 ...
0
votes
2answers
88 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 ...
1
vote
1answer
204 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 ...
4
votes
1answer
160 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 ...
0
votes
1answer
129 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 ...
1
vote
1answer
79 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 ...
1
vote
2answers
786 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. ...
6
votes
1answer
193 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.
1
vote
1answer
191 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 ...
1
vote
1answer
180 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 ...
1
vote
1answer
116 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 ...
2
votes
2answers
306 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 ...
4
votes
1answer
200 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 ...
3
votes
1answer
236 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 ...
0
votes
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 ...
2
votes
2answers
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 ...
1
vote
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?
2
votes
2answers
792 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?
1
vote
1answer
92 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 ...
3
votes
2answers
328 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?