9 Feite oor KrCl4 Lewis-struktuur en -kenmerke: Hoekom en hoe


KrCl4 or krypton tetrachloride is a tetra-coordinated halogenated compound having a molar mass of 225.61 g/mol. Let us discuss KrCl4 volledig.

KrCl4 is a compound of the inert element of Kr, and Kr generally cannot react with other elements but due to the presence of electronegative Cl atoms the threshold energy between them is almost equal. The molecule is reactive due to the presence of four electronegative atoms and there are four sigma bonds.

Let us have a look at some important topics of KrCl4 soos Lewis-struktuur, hibridisasie, bindingshoek en valenselektrone met behoorlike verduidelikings in die volgende artikel.

1. How to draw the KrCl4 lewis struktuur

Lewis’s structure of KrCl4 can give us a clear idea about the molecular property of KrCl4. Let us try to draw the lewis structure of KrCl4 in verskillende volgende stappe.

Tel die valenselektrone

Counting the valence electrons for a molecule is the first redrawing drawing its lewis structure properly. Here the total valence electrons are 36. Now we can explain these valence electrons, by adding valence electrons of Kr as 8 and for four Cl atoms as 7 each, and we just added them together.

Die keuse van die sentrale atoom

Choosing the central atom for drawing the lewis structure is another important step. Here Kr is chosen as the central atom because of two reasons. The first reason is the size of Kr is larger than Cl so it can accumulate all the atoms surrounding itself and the second reason Kr is more electropositive than Cl.

Bevredig die oktet

Always it should be checked while drawing lewis’s structure that every atom should obey the octet rule by completing its valence orbital either accept or share electrons from others. So, here Kr has four electrons shared with four Cl atoms and two pairs of lone pairs and each Cl shares one electron to follow the octet.

Bevredig die valensie

To obey octet total electrons required for KrCl4 are 8+(4*8) = 40 but total valence electrons are 36, so to satisfy the valency of each atom we should add ½(40-36) = 2 bonds, but Kr is hexavalent so it forms four sigma bonds with four Cl atoms and two lone pairs and each Cl forms one bond satisfying their mono valency.

Ken die eensame pare toe

In the last step, we assign the non-bonded electrons over respective atoms. Those electrons are coming lastly after satisfying the valency. Kr has 8 valence electrons and only four electrons are involved in the bond formation. The remaining four electrons and six electrons of each Cl exist as lone pairs over them.

2. KrCl4 Lewis struktuur vorm

Lewis structure shape is very particular for that molecule who has the same environment. Now we try to learn about the shape of KrCl4 in die volgende afdeling.

The Shape of the KrCl4 is vierkantige vlak according to the following table,

Molekulêre
Formule
Aantal van
verbandpare
Aantal van
alleenpare
Vorm  meetkunde    
AX10lineêre  lineêre
AX2        20lineêre   lineêre  
AX       11lineêre  lineêre  
AX330Driehoekig
planêre
Driehoekig
planêre
AX2E     21gebuigDriehoekig
planêre
AX2     12lineêre  Driehoekig
planêre
AX440tetraëdriesetetraëdriese
AX3E     31Driehoekig
piramidale        
tetraëdriese
AX2E2                2gebuigtetraëdriese
AX3                     13lineêre  tetraëdriese
AX550trigonaal
bipiramidaal
trigonaal
bipiramidaal
AX4E     41wipplanktrigonaal
bipiramidaal
AX3E2    32 t-vormig         trigonaal
bipiramidaal
AX2E3    23lineêre   trigonaal
bipiramidale
AX660oktaëdrieseoktaëdriese
AX5E     51             vierkante
piramidale   
oktaëdriese
AX4E2                    42vierkante
piramidale 
oktaëdriese
VSEPR Tabel
KrCl4 Molekulêre vorm

Due to the presence of two pairs of lone pairs, it is an AX4E2 type of molecule as per VSEPA (Valence Shell Electrons Pair Theory) and it adopted a square planar shape but its geometry is octahedral. Four Cl atoms present four corners of the square planar moiety.

3. KrCl4 valenselektrone

With the help of valence electrons, each atom can form a stable bond with another, and also the valency will be justified. Let us calculate the total valence electrons for KrCl4.

The total valence electrons of KrCl4 is 36 because 8 electrons come from Kr and for each Cl is 7, so for 4 Cl atoms the numbers are 28, and we just add them by their stoichiometric ratio. So, the valence electrons of KrCl4 is die som van elke atoom.

  • Kom ons bereken die totale valenselektrone vir die stelsel afsonderlik.
  • The valence electrons for central Kr are 8
  • The valence electrons for the surrounding Cl atom are 7
  • So, total valence electrons for KrCl4 is 8+(7*4) = 36

4. KrCl4 lewis struktuur oktet reël

To satisfy the valency of each atom they obey the octet after the bond formation by completing their valence orbital. Now discuss the octet of KrCl4 volledig.

Kr already completed its octet as it is a noble gas and its configuration is [Ar] 3d¹⁰ 4s² 4p⁶ and Cl needs to complete the octet during the bond formation. Because its valence shell is not completed as its configuration is [Ne]3s23p6. During the bond formation, each Cl shares one electron and completed its octet.

To obey the octet for p block Kr and Cl, the total need of electrons will be 8+(4*8) =40. But the valence electrons are 36, so the remaining electrons are accumulating by 4/2 = 2 bonds to satisfy their valency. By completing the octet Kr, as well as Cl, are satisfied by their stable valency by forming a single bond.

5. KrCl4 lewis struktuur eensame pare

Lone pairs are those valence electrons that are not participating in the bond formation they are non-bonded electrons. Let us count the lone pairs of KrCl4.

KrCl4 has 14 pairs of lone pairs or 28 lone pairs of electrons present which are coming from the Kr and Cl. Because Kr has 8 valence electrons and only 4 electrons are being used in bond formation. In Cl, there are 7 valence electrons and only 1 electron is used in bond and the rest electrons exist in lone pairs.

  • Eensame pare word bereken deur die volgende formule, nie-gebonde elektrone = valenselektrone – bindelektrone.
  • The lone pair over Kr is, 8-4 = 4
  • The lone pairs over Cl is, 7-1 = 6
  • So, the total lone pairs of KrCl4 is 4 + (6*4) = 28 lone pairs of electrons.

6. KrCl4 Lewis struktuur hoek

A bond angle is that angle makes by the atoms which are present in a molecule for proper orientation and shape. Now calculate the bond angle of KrCl4 in die volgende deel.

The bond angle Cl-Kr-Cl is perfect 900 as because it exists as a square pyramidal shape so the bond angle is the ideal value. All the Cl atoms make the perfect 900 bond angle with central Kr and the lone pairs present over Kr are far away due to the larger size of Kr. So there is no chance of lone pairs repulsion.

KrCl4 Bindingshoek
  • Actually, the bond angle is predicted by the bents rule of hybridization, COSθ = (p-1)/p.
  • The hybridization of KrCl4 is sp3d2, so p character is 3/6th or ½.
  • So, the bond angle is, COSθ = [(1/2)-1]/(1/2)
  • Θ = COS-1(-1) = 1800
  • So the bond angle is 1800-900 = 900.

7. KrCl4 Lewis struktuur formele aanklag

With the concept of formal charge, we can predict the magnitude of charge and which atom accumulates that can be calculated. Let us calculate the formal charge for KrCl4.

The formal charge of KrCl4 is 0 because the net formal charge possessed by the individual atoms is 0 and for this reason, the total formal charge is 0. The molecule is stable and each atom present over the molecule is satisfied by its oxidation state and valency, so no charge will appear on the molecule.

Kom ons kontroleer die waarde van die formele lading teenwoordig oor H of P deur die formule, FC = Nv - NLP -1/2 Nbp

  • The formal charge over the Kr atom is, 8-4-(8/2) = 0
  • The formal charge of the over Cl atom is, 7-6-(2/2) = 0
  • So, from the above data, it is confirmed KrCl4 is an electrically stable molecule with 0 formal charges.

8. KrCl4 lewis struktuur resonansie

Resonance is the delocalization of electron clouds through different skeleton forms of the molecule. Let’s see whether is possible for a KrCl4 resonerende struktuur of nie.

KrCl­4 shows resonance due to the presence of lone pairs over Cl acts as excess electronic clouds and can be delocalized over the Kr through the bond. KrCl4 shows generally two resonating structures. One is more stable and another is less stable based on the number of covalent bonds and charges.

KrCl4 Resonerende strukture

Structure I is more stable as it contains the same number of covalent bonds as structure II but no charge appears over the molecule. But structure II contains one double bond between Kr and Cl but the positive charge appears over the electronegative Cl atoms which is a destabilizing factor and it has a lower contribution.

9. KrCl4 verbastering

verbastering is a theoretical concept by which the mixing of atomic orbitals forms a new hybrid orbital of equivalent energy. Let us predict the hybridization of KRCL4.

KrCl4 is sp3d2 hybridized which is confirmed in the following table,

struktuur   verbastering
waarde  
Toestand van
verbastering
van sentrale
atoom
Bond
hoek
1.Lineêr          2         sp /sd / pd1800
2.Beplanner
trigonaal      
3sp2                   1200
3.Tetraëdraal 4sd3/ sp3109.50
4.Trigonaal
bipiramidaal
5sp3d/dsp3900 (aksiaal),
1200(ekwatoriaal)
5.Oktaedraal         sp3d2/
d2sp3
900
6.Vyfhoekig
bipiramidaal
7sp3d3/
d3sp3
900, 720
Hibridiseringstabel
KrCl4 verbastering
  • Ons kan die hibridisasie bereken deur die konvensie formule, H = 0.5(V+M-C+A),
  • So, the hybridization of central Kr is, ½(8+4+0+0) = 6 (sp3d2)
  • One s orbital, three p orbitals and two d orbitals of Kr are involved in the hybridization.
  • The lone pairs over Kr are also involved in the hybridization.

10. Is KrCl4 polêr of nie-polêr?

Polarity or non-polarity depends on the presence of the dipole-moment created by the atoms of the molecule. Let us see whether KrCl4 polêr is of nie.

KrCl4 is a non-polar molecule because of its symmetric shape of the molecule. All the directions of the dipole moment will cancel out each other due to the symmetric shape of the molecule. The magnitude of dipole-moment is always the same because all the surrounding atoms are Cl.

Gevolgtrekking

KrCl4 molecule is more reactive because all the sigma electron density of each bond is being dragged away to the electronegative Cl site. So, the bonds become weaker and easily be cleaved and it is used as a chlorinating agent in organic reactions.

Biswarup Chandra Dey

Hi......Ek is Biswarup Chandra Dey, ek het my Meestersgraad in Chemie van die Sentrale Universiteit van Punjab voltooi. My spesialiteitsgebied is Anorganiese Chemie. Chemie gaan nie net oor lees reël vir reël en memoriseer nie, dit is 'n konsep om op 'n maklike manier te verstaan ​​en hier deel ek met jou die konsep oor chemie wat ek leer omdat kennis die moeite werd is om dit te deel.

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