Periodic Table - Transition Metals - Nickel Chemistry - Doc Brown's Chemistry  Revising Advanced Level Inorganic Chemistry Periodic Table Revision Notes

Part 10. Transition Metals 3d–block:

10.10 Nickel Chemistry

The chemistry of nickel is dominated by the +2 oxidation state with many nickel(II) complexes known.

principal oxidation states of nickel, redox reactions of nickel, ligand substitution displacement reactions of nickel, balanced equations of nickel chemistry, formula of nickel complex ions, shapes colours of nickel complexes, formula of compounds


PLEASE NOTE this page on the 3d block transition metal nickel is for Advanced A Level students ONLY!

Therefore it is IMPORTANT for GCSE/IGCSE/O Level students studying iron chemistry to go to  ...

(c) doc b GCSE/IGCSE Periodic Table Revision Notes  or   (c) doc b GCSE/IGCSE Transition Metals Revision Notes including nickel

INORGANIC Part 10 3d block TRANSITION METALS sub–index: 10.1–10.2 Introduction 3d–block Transition Metals * 10.3 Scandium * 10.4 Titanium * 10.5 Vanadium * 10.6 Chromium * 10.7 Manganese * 10.8 Iron * 10.9  Cobalt * 10.10 Nickel * 10.11 Copper * 10.12 Zinc * 10.13 Other Transition Metals e.g. Ag and Pt * Appendix 1. Hydrated salts, acidity of hexa–aqua ions * Appendix 2. Complexes & ligands * Appendix 3. Complexes and isomerism * Appendix 4. Electron configuration & colour theory * Appendix 5. Redox equations, feasibility, Eø * Appendix 6. Catalysis * Appendix 7. Redox equations * Appendix 8. Stability Constants and entropy changes * Appendix 9. Colorimetric analysis and complex ion formula * Appendix 10 3d block – extended data * Appendix 11 Some 3d–block compounds, complexes, oxidation states & electrode potentials * Appendix 12 Hydroxide complex precipitate 'pictures', formulae and equations

Advanced Level Inorganic Chemistry Periodic Table Index * Part 1 Periodic Table history * Part 2 Electron configurations, spectroscopy, hydrogen spectrum, ionisation energies * Part 3 Period 1 survey H to He * Part 4 Period 2 survey Li to Ne * Part 5 Period 3 survey Na to Ar * Part 6 Period 4 survey K to Kr and important trends down a group * Part 7 s–block Groups 1/2 Alkali Metals/Alkaline Earth Metals * Part 8  p–block Groups 3/13 to 0/18 * Part 9 Group 7/17 The Halogens * Part 10 3d block elements & Transition Metal Series * Part 11 Group & Series data & periodicity plots * All 11 Parts have their own sub–indexes near the top of the pages


10.10. Chemistry of Nickel Ni, Z=28, 1s22s22p63s23p63d84s2 

data comparison of nickel with the other members of the 3d–block and transition metals

Z and symbol 21 Sc 22 Ti 23 V 24 Cr 25 Mn 26 Fe 27 Co 28 Ni 29 Cu 30 Zn
property\name scandium titanium vanadium chromium manganese iron cobalt nickel copper zinc
melting point/oC 1541 1668 1910 1857 1246 1538 1495 1455 1083 420
density/gcm–3 2.99 4.54 6.11 7.19 7.33 7.87 8.90 8.90 8.92 7.13
atomic radius/pm 161 145 132 125 124 124 125 125 128 133
M2+ ionic radius/pm na 90 88 84 80 76 74 72 69 74
M3+ ionic radius/pm 81 76 74 69 66 64 63 62 na na
common oxidation states +3 only +2,3,4 +2,3,4,5 +2,3,6 +2,3,4,6,7 +2,3,6 +2,3 +2,+3 +1,2 +2 only
outer electron config. [Ar]... 3d14s2 3d24s2 3d34s2 3d54s1 3d54s2 3d64s2 3d74s2 3d84s2 3d104s1 3d104s2
Elect. pot. M(s)/M2+(aq) na –1.63V –1.18V –0.90V –1.18V –0.44V –0.28V –0.26V +0.34V –0.76V
Elect. pot. M(s)/M3+(aq) –2.03V –1.21V –0.85V –0.74V –0.28V –0.04V +0.40 na na na
Elect. pot. M2+(aq)/M3+(aq) na –0.37V –0.26V –0.42V +1.52V +0.77V +1.87V na na na

Elect. pot. = standard electrode potential data for nickel (EØ at 298K/25oC, 101kPa/1 atm.)

na = data not applicable to nickel

Extended data table for NICKEL

property of nickel/unit value for Ni
melting point Ni/oC 1455
boiling point Ni/oC 2730
density Ni/gcm–3 8.90
1st Ionisation Energy Ni/kJmol–1 737
2nd IE/kJmol–1 1753
3rd IE/kJmol–1 3393
4th IE/kJmol–1 5300
5th IE/kJmol–1 7280
atomic radius Ni/pm 125
Ni2+ ionic radius/pm 72
Relative polarising power Ni2+ ion 2.8
Ni3+ ionic radius/pm 62
Relative polarising power Ni3+ ion 4.8
oxidation states of Ni, less common/stable +2, +3
simple electron configuration of Ni 2,8,16,2
outer electrons of Ni [Ar]3d84s2
Electrode potential Ni(s)/Ni2+(aq) –0.26V
Electrode potential Ni(s)/Ni3+(aq) na
Electrode potential Ni2+(aq)/Ni3+(aq) na
Electronegativity of Ni 1.91

 

  • Uses of NICKEL

    • Nickel is a moderately hard silvery–white metal, lustrous like most transition metals and malleable and ductile.

    • Nickel is quite resistant to corrosion and not affected by water but will dissolve slowly in most strong acids.

    • Nickel has many uses from 'silver' coinage metals like cupro–nickel, which is an alloy of nickel and copper that doesn't readily corrode.

    • Along with chromium, nickel is used in stainless steels.

    • Alnico alloy (Al + Ni + Co) is used to make permanent magnets.

    • Nichrome wire (Ni + Cr) is used to make wire for windings in electric motors.

    • Nickel is a constituent of monel metal alloy used to make ships propeller shafts and chemical reactor vessels because of its strength and anti–corrosion properties.

    • Nickel is an important hydrogenation catalyst in converting unsaturated vegetable oils to saturated fats like margarine.

      • unsaturated oil + hydrogen ==> low melting solid more saturated fat

      • Along the carbon chain of the vegetable oil you get: –CH=CH– + H2 ==> –CH2–CH2

      • This reaction is described in detail at the end of my nickel notes.

    • Solutions of nickel(II) salts or complexes are used in electroplating nickel onto other metal surfaces.

      • e.g. the complex ion salt Ni(NH4)2(SO4)2.6H2O

    • Nickel(II) oxide, NiO, is used in pigments.

  • Biological role of nickel

    • It is apparently found in human tissue, but its role is unknown.


The Chemistry of NICKEL

Pd s block d blocks (3d block nickel) and f blocks of metallic elements p block elements
Gp1 Gp2 Gp3/13 Gp4/14 Gp5/15 Gp6/16 Gp7/17 Gp0/18
1

1H

2He
2 3Li 4Be The modern Periodic Table of Elements

ZSymbol, z = atomic or proton number

3d block of metallic elements: Scandium to Zinc focus on nickel

5B 6C 7N 8O 9F 10Ne
3 11Na 12Mg 13Al 14Si 15P 16S 17Cl 18Ar
4 19K 20Ca 21Sc

[Ar]3d14s2

scandium

22Ti

[Ar]3d24s2

titanium

23V

 [Ar] 3d34s2

vanadium

24Cr

[Ar] 3d54s1

chromium

25Mn

   [Ar]   3d54s2

manganese

26Fe

[Ar] 3d64s2

iron

27Co

[Ar] 3d74s2

cobalt

28Ni

[Ar] 3d84s2

nickel

29Cu

[Ar] 3d104s1

copper

30Zn

[Ar] 3d104s2

zinc

31Ga 32Ge 33As 34Se 35Br 36Kr
5 37Rb 38Sr 39Y 40Zr 41Nb 42Mo 43Tc 44Ru 45Rh 46Pd 47Ag 48Cd 49In 50Sn 51Sb 52Te 53I 54Xe
6 55Cs 56Ba 57,58-71 72Hf 73Ta 74W 75Re 76Os 77Ir 78Pt 79Au 80Hg 81Tl 82Pb 83Bi 84Po 85At 86Rn
7 87Fr 88Ra 89,90-103 104Rf 105Db 106Sg 107Bh 108Hs 109Mt 110Ds 111Rg 112Cn 113Uut 114Fl 115Uup 116Lv 117Uus 118Uuo
  *********** *********** ************ ************ ************** ********** ********** ********** ********** **********  

  • The electrode potential chart highlights the values for various oxidation states of nickel.

  • NICKEL(II) CHEMISTRY

  • In aqueous solution nickel forms the green stable hexaaqua nickel(II) ion, [Ni(H2O)6]2+(aq) from eg nickel(II) chloride solution NiCl2(aq) or nickel(II) sulfate NiSO4(aq), both of which are suitable for laboratory experiments for investigating the aqueous chemistry of the nickel(II) ion..

  • With alkalis sodium hydroxide or ammonia, nickel(II) ions produce the hydrated nickel(II) hydroxide green? precipitate. There is no further reaction with excess of NaOH, but see further down for excess NH3.

    • Ni2+(aq) + 2OH(aq) ==> Ni(OH)2(s) 

      • This precipitation reaction can be written as

      • [Ni(H2O)6]2+(aq) + 2OH(aq) ==>  [Ni(OH)2(H2O)4] + 2H2O(l)

      • The two nickel(II) complexes are octahedral in shape with a co-ordination number of 6 from 6 unidentate ligands.

      • The overall charge on the nickel(II) hydroxide complex is zero, the 2OH- cancelling out the Ni2+.

      • This is an example of a nickel complex ligand exchange reaction, two hydroxide ions displacing two water molecules.

      • Water and the hydroxide ion are monodentate (unidentate ligands), that is each ligand can donate a single pair of electrons to form one co-ordinate bond (dative covalent bond).

      • In most ligand exchange reactions there is no change in oxidation state unless a reducing agent or oxidising agent is present.

      • Transition metal commonly form octahedral complexes, like those of nickel, with small ligands like water, ammonia and hydroxide ion.

  • With alkaline aqueous sodium carbonate solutions, nickel(II) ions produces a precipitate of green ppt. of nickel(II) carbonate.

    • Ni2+(aq) + CO32–(aq) ==> NiCO3(s) 

      • Its actually a basic carbonate – a mixture of the hydroxide and carbonate, you can make the pure carbonate by using sodium hydrogencarbonate solution.

      • Ni2+(aq) + 2HCO3(aq) ==> NiCO3(s) + 4H2O(l) + CO2(g)

  • With excess aqueous ammonia the blue hexammine complex ion is formed from the hexaaquanickel(II) ion – a typical ligand substitution reaction giving the hexaamminenickel(II) ion:

  • [Ni(H2O)6]2+(aq) + 6NH3(aq) [Ni(NH3)6]2+(aq) + 6H2O(l)

    • The two nickel(II) complexes are octahedral in shape with a co-ordination number of 6.

    • The overall charge on the nickel(II) hydroxide complex remains 2+ because both ligands are electrically neutral.

    • This is another example of a nickel complex ligand exchange reaction where six ammonia molecules replace six water molecules.

    • Kstab = {[Ni(NH3)6]2+(aq)} / {[Ni(H2O)6]2+(aq)} [NH3(aq)]6

    • Kstab = 4.8 x 107 mol–6 dm18  [lg(Kstab) = 7.7]

    • You can write equation of the ammine complex from the dissolving of nickel(II) hydroxide precipitate.

      • Ni(OH)2(s) + 6NH3(aq) [Ni(NH3)6]2+(aq) + 2OH(aq)

    • Ligand substitution may be incomplete, so, with lower concentrations of ammonia the pale blue complex can also have the structure [Ni(H2O)2(NH3)4]2+

  • The hexaaquanickel(II) ion also forms complexes with other amine ligands

    • e.g. the bidentate ligand 1,2–diaminoethane (H2N–CH2–CH2–NH2), often abbreviated to en from its old trivial name of ethylenediamine). Each of the lone pairs of electrons on the nitrogen atoms can form a co-ordinate bond

    • [Ni(H2O)6]2+(aq) + 3en(aq) [Ni(en)3]2+(aq) + 6H2O(l)

      • This is an example of a chelation substitution reaction where a bidentate or multidentate ligand displaces a numerically greater monodentate (unidentate) ligands.

      • The resulting nickel complex is described as an example of a chelate.

      • Kstab = {[Ni(en)3]2+(aq)} / {[Ni(H2O)6]2+(aq)} {[en(aq)]3}

      • Kstab = 2.0 x 1018 mol–3 dm9 [lg(Kstab) = 18.3]

      • The reaction is almost completely 100% to the right.

      • Notice that the Kstab is greater than the Kstab for the formation of the ammine complex, so you can correctly predict that the following ligand exchange will take place ...

      • [Ni(NH3)6]2+(aq) + 3en(aq) [Ni(en)3]2+(aq) + 6NH3(aq)

      • I've used en for simplicity, but the formula of the complex formed is [Ni(H3NCH2CH2NH3)3]2+

      • Although then enthalpy changes for these reactions are similar, because a similar number of similar covalent bonds are broken or made, the release of the larger number of smaller molecules leads to a large increase in entropy (a large positive ΔS).

      • This makes the free energy change, calculated from ΔG = ΔH - TΔS, more negative, therefore more feasible for these nickel complex reactions.

  • The complex with EDTA is also readily formed. EDTA is an even more powerful chelating agent with an extremely high Kstab values.

    • [Ni(H2O)6]2+(aq) + EDTA4–(aq) ===> [Ni(EDTA)]2–(aq) + 6H2O(l)

    • Kstab = {[Ni(EDTA)3]2–(aq)} / {[Ni(H2O)6]2+(aq)} {[EDTA4–(aq)]}

    • Kstab = 1.0 x 1019 mol–1 dm3 [lg(Kstab) = 19.0]

    • Note that Kstab for the same ion tend to increase the greater the chelating power of an individual ligand in terms of the ligand bond formed – mainly due to the increase in entropy as more particles are formed by the polydentate ligands displacing the unidentate ligands.

    • e.g. for the same nickel(II) ion Kstab(EDTA) > Kstab(en) > Kstab(NH3)

    • That is from left to right in the sequence, the entropy change decreases, multidentate > bidentate > monodentate (unidentate)

  • VIEW ppts. with OH, NH3 and CO32–, & complexes, if any, with excess reagent.

  • Other complexes of nickel

    • Nickel carbonyl, Ni(CO)4, is a neutral complex tetrahedrally shaped covalent molecule. Note (i) nickel is in a zero oxidation state and (ii) the ligand CO also acts as ligand with haemoglobin (hemoglobin) in carbon monoxide poisoning.

    • Ni2+ forms the tetrachloronickelate(II) ion, [NiCl4]2–, a tetrahedral anionic complex with the chloride ion ligand (Cl).

      • [Ni(H2O)6]2+(aq) + 4Cl(aq) ==> [NiCl4]2–(aq) + 6H2O(l)

      • In this ligand exchange reaction, the nickel(II) complex ion shape changes from octahedral to tetrahedral, the co-ordination number changes from 6 to 4, but the oxidation state of nickel remains at +2. The overall electrical charge on the chloro complex is 2- (from 2+/+2 and 4x-1).

      • Its likely that the more bulky chloride ion (radius Cl > C) 'forces' the formation of the tetrahedral shape rather than a square planar shaped complex in the reaction described below.

      • Kstab = {[NiCl4]2–(aq)} / {[Ni(H2O)6]2+(aq)} [Cl(aq)]4

      • Kstab = ? mol4 dm–12  [lg(Kstab) = ?]

    • Ni2+ forms the tetracyanonickelate(II) ion, [Ni(CN)4]2–, a square planar anionic complex with the cyanide ion (CN).

      • [Ni(H2O)6]2+(aq) + 4CN(aq) ==> [NiCN4]2–(aq) + 6H2O(l)

      • Similar to above, in this ligand exchange reaction, the nickel(II) complex ion shape changes from octahedral to square planar, the co-ordination number changes from 6 to 4, but the oxidation state of nickel remains at +2. The overall electrical charge on the chloro complex is 2- (from 2+/+2 and 4x-1).

      • Kstab = {[NiCN4]2–(aq)} / {[Ni(H2O)6]2+(aq)} [CN(aq)]4

      • Kstab = 2 x 1031 mol4 dm–12  [lg(Kstab) = 31.3]

  • Summary of some complexes–compounds & oxidation states of nickel compared to other 3d–block elements

  • An example of the catalytic action of nickel metal.

    • An example of nickel acting as a heterogeneous catalysis is illustrated above, the hydrogenation of alkenes (e.g. ethene + hydrogen ===> ethane).  An extremely important process in the food industry or converting unsaturated oils into hydrogenated solid fats.

    • Nickel is the solid phase catalyst and the reactant gases in the different gaseous phase.

    • In terms of activation energies, with reference to the reaction profile below:

      • (1) ==> (2) is represented by Ea1, the absorption of the reactant molecules onto the catalyst surface to form the intermediate state between nickel and the adsorbed gases..

      • (3) represents the minimum potential energy trough where the molecules are adsorbed onto the catalyst surface.

      • (2) ==> (3-5) is represented by Ea2 the formation of the products form the intermediate absorbed states of the molecules.

      • A two stage reaction profile for a catalytic cycle (Ea = activation energy)

        • This sort of diagram is most applicable to homogeneous catalysis where definite intermediates are formed, but in general principle it applies to heterogeneous catalysis too where the adsorption (particularly chemical) is equivalent to forming a transition state or complex.

        • Ea1 is the activation energy leading to the formation of an intermediate complex between nickel and the adsorbed gases.

        • Ea2 is the activation energy for the change of the intermediate complex into product (ethane).

        • Ea3 is the activation energy of the uncatalysed reaction between nickel and hydrogen.


PLEASE NOTE this page on the 3d block transition metal nickel is for Advanced A Level students ONLY!

Therefore it is IMPORTANT for GCSE/IGCSE/O Level students studying iron chemistry to go to  ...

(c) doc b GCSE/IGCSE Periodic Table Revision Notes  or   (c) doc b GCSE/IGCSE Transition Metals Revision Notes including nickel


physical and chemical properties of the 3d block transition metal nickel, oxidation and reduction reactions of nickel ions, outer electronic configurations of nickel, principal oxidation states of nickel, shapes of nickel's complexes, octahedral complexes of nickel, tetrahedral complexes of nickel, square planar complexes of nickel, stability data for nickel's complexes, aqueous chemistry of nickel ions, redox reactions of nickel ions, physical properties of nickel, melting point of nickel, boiling point of nickel, electronegativity of nickel, density of nickel, atomic radius of nickel, ion radius of nickel, ionic radii of nickel's ions, common oxidation states of nickel, standard electrode potential data for nickel, ionisation energies of nickel, polarising power of nickel ions, industrial applications of nickel compounds, chemical properties of nickel compounds, why are nickel complexes coloured?, isomerism in the complexes of nickel, formulae of nickel compounds, tests for nickel ions keywords redox reactions ligand substitution displacement balanced equations formula complex ions complexes ligand exchange reactions redox reactions ligands colours oxidation states: nickel ions Ni(0) Ni2+ Ni(+2) Ni(II) NiCl2 NiSO4 Ni2+ + 2OH– ==> Ni(OH)2 Ni2+ + CO32– ==> NiCO3 Ni2+ + 2HCO3– ==> NiCO3 + 4H2O + CO2 [Ni(H2O)6]2+ + 6 NH3 [Ni(NH3)6]2+ + 6H2O [Ni(H2O)6]2+ + 6NH3 ==> [Ni(NH3)6]2+ + 6 H2O Kstab = {[Ni(NH3)6]2+} / {[Ni(H2O)6] 2+} [NH3]6 Ni(OH)2 + 6NH3 [Ni(NH3)6]2+ + 2OH– [Ni(H2O)6]2+ + 3en ===> [Ni(en)3]2+ + 6H2O Kstab = {[Ni (en)3]2+} / {[Ni(H2O)6]2+} {[en]3} [Ni(H2O)6]2+ + EDTA4– ===> [Ni(EDTA)]2– + 6H2O Kstab = {[Ni(EDTA)3]2–} / {[Ni (H2O)6]2+} {[EDTA4–]}[Ni(H2O)6]2+ + 4 Cl– ==> [NiCl4]2– + 6H2O Kstab = {[NiCl4]2–} / {[Ni(H2O)6]2+} [Cl–]4 [Ni(H2O)6]2+ + 4 CN– ==> [NiCN4]2– + 6H2O Kstab = {[NiCN4]2–} / {[Ni(H2O)6]2+} [CN–]4 Kstab = 2 x 1031 mol4 dm–12 [lg(Kstab) = 31.3] oxidation states of nickel, redox reactions of nickel, ligand substitution displacement reactions of nickel, balanced equations of nickel chemistry, formula of nickel complex ions, shapes colours of nickel complexes  Na2CO3 NaOH NH3 nickel chemistry for AQA AS chemistry, nickel chemistry for Edexcel A level AS chemistry, nickel chemistry for A level OCR AS chemistry A, nickel chemistry for OCR Salters AS chemistry B, nickel chemistry for AQA A level chemistry, nickel chemistry for A level Edexcel A level chemistry, nickel chemistry for OCR A level chemistry A, nickel chemistry for A level OCR Salters A level chemistry B nickel chemistry for US Honours grade 11 grade 12 nickel chemistry for pre-university chemistry courses pre-university A level revision notes for nickel chemistry  A level guide notes on nickel chemistry for schools colleges academies science course tutors images pictures diagrams for nickel chemistry A level chemistry revision notes on nickel chemistry for revising module topics notes to help on understanding of nickel chemistry university courses in science careers in science jobs in the industry laboratory assistant apprenticeships technical internships USA US grade 11 grade 11 AQA A level chemistry notes on nickel chemistry Edexcel A level chemistry notes on nickel chemistry for OCR A level chemistry notes WJEC A level chemistry notes on nickel chemistry CCEA/CEA A level chemistry notes on nickel chemistry for university entrance examinations biological role of cobalt nickel is unknown, nickel(II) chemistry, shape and formula of complexes of nickel(II) Ni2+, complexes of nickel with ammonia, oxidation of nickel(II) ion Ni2+ to the nickel(III) ion Ni3+, reactions of the nickel(II) ion Ni2+ with hydroxide ion, structure formula and shape of nickel carbonyl, colour and structure of nickel(III) Ni3+ complexes, formula of EDTA complexes of nickel, tetrahedral complexes of nickel with chloride ion ligands, octahedral complexes of nickel(II) ion Ni2+ with cyanide and water ligands, octahedral complexes of nickel(III) Ni3+

Scandium * Titanium * Vanadium * Chromium * Manganese * Iron * Cobalt * Nickel * Copper * Zinc * Silver & Platinum

Introduction 3d–block Transition Metals * Appendix 1. Hydrated salts, acidity of hexa–aqua ions * Appendix 2. Complexes & ligands * Appendix 3. Complexes and isomerism * Appendix 4. Electron configuration & colour theory * Appendix 5. Redox equations, feasibility, Eø * Appendix 6. Catalysis * Appendix 7. Redox equations * Appendix 8. Stability Constants and entropy changes * Appendix 9. Colorimetric analysis and complex ion formula * Appendix 10 3d block – extended data * Appendix 11 Some 3d–block compounds, complexes, oxidation states & electrode potentials * Appendix 12 Hydroxide complex precipitate 'pictures', formulae and equations


PLEASE NOTE this page on the 3d block transition metal nickel is for Advanced A Level students ONLY!

Therefore it is IMPORTANT for GCSE/IGCSE/O Level students studying iron chemistry to go to  ...

(c) doc b GCSE/IGCSE Periodic Table Revision Notes  or   (c) doc b GCSE/IGCSE Transition Metals Revision Notes including nickel

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