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InorgChem d-Block Elements

Properties

TRANSITIONELEMENTSare elements, which forms at least one compound in which the element has inincompletely filled inner dsu!shell

"lements with at least one o#idation state in which the element has incompletely filled

inner dsu!shell $i.e. w/1 to 9 e%&

'candium $'c& ( )inc $*n& are not transition elements as !oth has only one o#idationstate 'c+( *n2, which !oth has no incompletely filled dsu!shell

d-BLOCKELEMENTSare elements whose highestenergy electron / lastfilled

electron is found in the dor!ital

"lement atoms with electronic configuration - $n+1&s2ndx

irst transition series0 'c, i, , 3r, 4n, e, 3o, i, 3u, *n

Electronic configuration: toms of d!loc elements are characteri)ed !y inner !uilding of dsu!shells

4ost contains the configuration - ndx$n+1&s2

"#cept0 3r $*2&0 -r+d5s1 and

3u $*29&0 -r+d1:s1

he 2 ions of d!loc elements ha;e no e%in the ;alencesor!ital

3onfiguration0 - ndx

Typical properties of Transition elements: Properties similar tos!loc elements

4etals

ard, strong, high 0 'trong ( closely paced struct. due to delocali)ation of s( +de%

'imilar chemical properties0 ?utermost su!shell s2

aria!le o#idation state0 'uccessi;e @" are close

!ility of formation of comple#es0 ;aila!ility of lowlying d;acant or!itals

3pds are colored0 'plitting of dsu!shell into different energy le;els after comple# formation3atalytic !eha;ior0 !ility to form comple#es ( the e#istence of ;aria!le o#idation states

'c ( *n do not e#hi!it typical properties of transition elements

Variation of PropertiesIonization Enthalpy: d=loc elements has d su!shell filled !efore +dsu!shell

=efore filling, shas lower energy than +d

fter filling dor!ital, +dhas lower energy than s

e%in dor!ital screens sas it is more penetrating

Ahen d!loc metal ioni)es, the se% are first remo;ed

Bifference in energy !tw +d( ssu!shells is small, successi;e @" increases gradually

cross the 1sttransition series, @" increases slightly

dditional e%is added to inner +dsu!shell and screens the se%, which is !eing ioni)ed

'creening effect cancels most the increase in "3

1st@" of 'c C *n >1st@" of D ( 3a as the "3 inc.

Bue to the small ( gradual increase in @", transition elements ha;e similar chemical properties


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Metallic Radius: actors affect the metallic radius of d!loc metals0

"3 on the outermost e%0 inc. from 'c to *n

Eepulsion !tw the delectrons0 inc. from 'c to *n

ll d!loc metals ha;e smaller atomic radii thans!loc in same period due to the inc. of "3

cross the period from 'c to *n,tomic radius dec. slightly from 'c to 3r0 'light increase of "3

3r to i ha;e nearly constant atomic radius0 @ncreasing "3 ( repulsion cancelled out

tomic radius inc from i to *n0 Eepulsion !tw e%increases as * increases

?;erall ;ariation in atomic radius is small $:.12 % :.16 nm&0 e%is in inner +dsu!shell

Ionic Radius: ariation of ionic radius of d!loc elements is similar to that of atomic radius

ll d!loc metals ha;e smaller ionic radii thans!loc due to the inc. of "3

cross the period, the ionic radius from 'c to 3u dec. slightly as the slightly inc. of "3

@onic radius of *n

2

is slightly larger than e#pected as the fullfilled +d

1:

produces a largerelectronic repulsion

Melting Point & Hardness: 4P ( >ardness of metal 4etallic !ond strength

d=loc elements usually ha;e higher 4P ( hardness

=oths( de%are delocali)ed to the electron sea and tae part in the metallic !ond

'trong metallic !ond

4ost d!loc elements are closely paced $3oordination num!er 12&

tomic radii of d!loc elements are smaller

4P =P as only small fraction of metallic !onds has to !e !roen in melting !ut all metallic

!onds are !roen in !oiling $i.e. =oiling tomi)ation&

actor affecting the 4P ( hardness of 'c to *n

'maller atomic radius 'tronger metallic !ond

4ore unpaired de%4ore delocali)ed e%in metallic !ond 'tronger metallic !ond

3loser pacing of atoms 'tronger metallic !ond

>alffilled or fullfilled dsu!shell are e#tra sta!le

cross the period from 'c to *n, the 4P ( hardness

@ncreased from 'c to as the no. of unpaired d e%inc. ( atomic radius dec.

4etallic !ond strength increases

Becreased from to 4n as 3r ( 4n has e#tra sta!le +d54etallic !ond strength dec.

@ncreased to a ma#. at e, 3o, i as unpaired d e%are more in;ol;ed in metallic !ond

Becreased from 3u to *n as !oth has e#tra sta!le +d1:

Density: d=loc elements usually ha;e higher densities thans!loc elements as the atoms are closely

paced

he density increases from 'c to 3u as the relati;e atomic mass increases while atomic radii are

appro#imately constant

*n has a lower density than 3u as the +d( se%are less in;ol;ed in metallic !ond

Farger atomic radius

Electronegativity: cross the period from 'c to *n, "3 increases

"lectronegati;ity generally increases

"ase of formation of metal ions dec.

4etallic character dec.

d=loc elements are less electropositi;e / more electronegati;e thans!loc elements

d=loc cations are less liely to form thans!loc

4n has a lower electronegati;ity than e#pected

Bue to low ioni)ation enthalpies0 "#tra sta!ility of 4n20 -r+d5

*n has particularly low electronegati;ity


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Bue to low ioni)ation enthalpies0 "#tra sta!ility of *n20 -r+d1:

he standard electrode potential $" & has a similar ;ariation with electronegati;ity

Ahen "3 on the outermost e%increases, " !ecomes more positi;e or less negati;e

!idation "tates: ransition metals show ;aria!le o#idation states0

'c 1, 2, + 'c+

i 1,2, +, i2, i+, i?2 1,2, +, , 5 2, +, ?2, ?2

3r 1,2, +,,5,6 3r2, 3r+, 3r, 3r?+4n 1,2, +, , 5,6, 7 4n2, 4n$?>&+, 4n?2, 4n?

2%, 4n?%

e 1, 2, +, , 5, 6 e2, e+

3o 1,2, +, , 5 3o2, 3o+, -3o62%

i 1, 2, +, i2, i+, i2?+, i?23u 1, 2, + 3u, 3u2

*n 1, 2 *n2

G3omple# only 4ost sta!le state ?#idation states

he e#istence of ;aria!le o#idation states due to gradual increases rather than sharp rapid rise of

successi;e @" of transition metal

cross the 1sttransition series,

rom 'c to 4n, the highest possi!le ? otal no. of e%in +d( s

4a#imum ? found in 4n$@@&

=y remo;al of all +d( selectrons from 4n

rom 4n onwards, the highest ? decreases as the no. of unpaired e%decreases

'ta!ility of a particular ? is related to e#tra sta!le state of half/fullfilled dor!ital

4n2( e+are particularly sta!le as they ha;e -r+d5config.

*n2is particularly sta!le as it has -r+d1:config.

"nthalpy of formation of an ion0 >f >atom @" >hyd

n ion of lower >fis energetically sta!le

n energetically sta!le ion $e.g. 3u& may !e unsta!le w.r.t. disproportionation0

3u$s&3u

$aH& >f 6:6 Imol%1

3u$s&3u2

$aH& >f 971 Imol%1 $less sta!le&

Bisproportionation0 23u$aH&3u$s& 3u2

$aH& > %21 Imol%1

?ccurs spontaneously ( energetically fa;ora!le

#ormation of $olored $pds: 4osts!loc metals form colorless cpds !ut most d!loc metals form colored cpds

"#ception0 'c+

, i

3u

, *n2

Ahen transition metal forms cpd,

he electrons insshell is remo;ed

dshell !ecomes the outermost shell

he dor!itals may split into different energy le;els in cpd

he splitting is due to the electronic repulsion !tw de%and FP e%of anion / ligand

@f the metal ion has dshell neither fullfilled nor empty, e%in lower energy le;el can Jump to a

higher or!ital

!sor!s electromagnetic radiation of a particular freHuency

!sorption in the ;isi!le light region maes the ion colored

3olor of aHueous ion0'c+ 3olorless

i+ Purple i 3olorless

2 iolet +


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Eadiation in ;isi!le spectrum is emitted when the e%falls !ac

Reaction %ith %ater: d=loc metals usually react slowly with water

he low reacti;ity of d!loc metals is due to its high @" ( >atom

"#ception0 'c hot water 'c$?>&+$aH& >2$g&

Vanadium & Manganeseanadium: anadium is a soft ( sil;erywhite metal

3ommon o#idation states0 2, +, , 5

Kellow ?2, =lue ?2, ?+( >2'?

anadium$&0

Bio#o;anadium$& ion ?2 is produced !y dissol;ing ammonium polytrio#o;anadate$&0

>?+$aq& 2>

$aq& ?2

$aq& >

$aq& >2?$&

?+%

$aq& 2>

$aq& ?2

$aq& >2?$&

either 5nor -$>2?&65e#ists as the charge density is e#tremely high

>ydrolysis occurs0 5$aq& 2>2?$aq&?2

$aq& >

$aq&

@t is a sta!le o#idation state of

anadium$& o#ide, 2?5, is an amphoteric o#ide0

2?5$s& 2>

$aq& 2?2

$aq& >2?$&

2?5$s& 6?>%

$aq& 2?+%

$aq& +>2?$&

anadium$@&0

?#o;anadium$@& ion ?2can !e produced !y reacting ?2with metal0

*n$s& *n2

$aq& 2e%

?2

$aq& 2>

$aq& e% ?2$aq& >2?$&

either nor -$>2?&6e#ists as the charge density is e#tremely high

anadium$@@@& ( anadium$@@&0

+and 2ions can !e produced !y reducing ?2!y metal0

?2$aq& 2>

$aq& e% +$aq& >2?$&

+$aq& e% 2$aq&

=y adding e#cess *n granules or *n amalgam in acidic condition $conc. >3l&,

?+%

$aq&?2

$aq&?2

$aq&+

$aq&2

$aq&

=oth +and 2ions are reducing and readily o#idi)ed !y air or water

Manganese: 4anganese is a hard, pinishgrey metal

3hemically acti;e and rapidly attaced !y hot water, steam or acid0

4n$s& 2>2?$& 4n$?>&2$s& >2$g&

4n$s& >2?$g& 4n?$s& >2$g&

4n$s& 2>

$aq& 4n2

$aq& >2$g&

3ommon o#idation state0 2, , 7

4anganese$@@&0

he pale pin 4n2ion is ;ery sta!le in acids $partly due to +d5config.&

@t forms comple# -4n$>2?&62in water and undergoes slight hydrolysis-4n$>2?&6

2$aq& -4n$?>&$>2?&5

$aq& >

$aq&

@n alaline medium, 4n2would !ecomes white 4n$?>&20

-4n$>2?&62

$aq& 2?>%

$aq& -4n$?>&2$>2?&5$s& 2>2?$&

he 4n$?>&2in alaline is readily o#idi)ed !y ?2, >2?2, ?3l%to unsta!le 4n$?>&+$s&

and finally to 4n?2$s&0

4n$?>&2$s& ?2$g& 2>2?$& 4n$?>&+$s&

24n$?>&+$s& $n%+&>2?$g& 4n2?+n>2?$s&

24n2?+n>2?$s& ?2$g& 4n?2$s& $2n&>2?$&

24n$?>&2$s& ?2$g&24n?2$s& 2>2?$&


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4anganese$@&0

4n?2is a dar !rown amphoteric solid w/strong o#idi)ing property0

4n?2$s& >

$aq& 2e% 4n2$aq& 2>2?$&

4n?can o#idi)e 3l%in >3l$aq&0

4n?2$s& >3l$aq&4n3l2$aq& 2>2?$& 3l2$g&

4n?can !e o#idi)ed !y strong o#idi)ing agent in !asic medium0

+4n?2$s& 6?>%

$aq& 3l?+%

$aq&+4n?2%

$aq& +>2?$& 3l%

$aq&

24n?2$s& ?>%

$aq& ?2$g&24n?2%

$aq& 2>2?$&

4anganese$@@&0

4n2?7is acidic co;alent compound

Purple manganate$@@& ion 4n?%is a powerful o#idi)ing agent0

cidic medium0 4n?%

$aq& 8>

$aq& 5e% 4n2$aq& >2?$&

laline medium0 4n?%

$aq& 2>2?$& +e% 4n?2$s& ?>

%$aq&

4n?%can react w/iron$@@@& ion0

4n?%

$aq& 8>

$aq& 5e2

$aq&4n2

$aq& >2?$& 5e+

$aq&

Complexes$omple!: comple# $coordination compound& is formed when a central metal ion/atom is attached !y

ligands in which the no. of ligands is greater than the normal ;alance of the central ion/atom

he metal ion/atom acts as an electron pair acceptor $Fewis acid or electrophile&

he metal ion/atom ought to !e has high positi;e charge density to attract the ligands

he ligand acts as an electron pair donor $Fewis !ase or nucleophile&

COMPLEX0 central metal ion/atom surrounded !y and dati;ely !onded to other ligands

LIGAND0 n ion or molecule containing at least one atom ha;ing a lone pair of electrons whichcan !e donated to the central cation or atom to form a dati;e co;alent !ond

COORDINATIONNUMBERof the central ion is the num!er of ligands !onded to the central ion

d=loc metal has strong tendency towards comple# formation as the a;aila!ility of lowlying

;acant or!itals ena!les metal ions to accept FP e%from ligands

'omenclature: 3oordination compounds are named according to the nomenclature recommended !y @LP3

@onic coordination compounds0

3ation is name !efore the anion

he ligands and central metal are named together as one word?rder of ligands0 nionic, eutral, 3ationic

"#ample0 -Pt3l2$>+&2 Bichlorotetraammineplatium$@&

ames of anionic ligands end in %o

ames of neutral ligands are the names of the molecules, e#pt >+, >2?, 3?, ?

ames of common ligands0

LIGAND PREFIX LIGAND PREFIX

=romide =r % =romo mmonia >+ mmine3hloride 3l% 3hloro Aater >2? Hua

3yanide 3% 3yano 3ar!on mono#ide 3? 3ar!onyl

luoride % luoro

>ydro#ide ?>% >ydro#o'ulphate$@& '?

2% 'ulphato

mide >2% mido

@f the no. of a particular ligand is more than one, the num!er is indicated w/


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4

FF

FF

F

F

4

F

FF

F

4

FF

FF

3u

33

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"#ample0 -e$3&6+% >e#acyanoferrate$@@@&

ames of common metals in anionic comple#es0

METAL NAME METAL NAME

itanium itanate icel icelate

3hromium 3hromate 3opper 3uprate

4anganese 4anganate *inc *incate

@ron errate Platinum Platinate3o!alt 3o!altate

@f the comple# is cationic or neutral, the name of the metal is unchanged

"#ample0 -3r3l2$>2?& BichlorotetraaHuachromium$@@@&

eutral coordination compounds0

he name of the comple# is the name of the cpd

(onding & "ta)ility: Figand contains FP e%which forms dati;e !onds with the central metal

Bifferent ligand has different tendency to donate their unshared electrons to form dati;e !ond

he strength of the dati;e co;alent !ond of differs as the ligands differ

ligand can !e replaced !y another ligand which form more strong dati;e !ond i.e. the ligand that of higher tendency to donate the electrons

Ahen a stronger ligands present, the weaer ligand would !e replaced0

-e$>2?&62

$aq& 63%

$aq& -e$3&6%

$aq& 6>2?$&

-i$>2?&62

$aq& 6>+$aq& -i$>+&62

$aq& 6>2?$&

@n the displacement of ligands of the comple#, usually there would !e color change

he formation of comple# or displacement of ligand is a stepwise reaction

@n -3u$>2?&62

$aq& >+$aq& -3u$>+&$>2?&22

$aq& >2?$&0

-3u$>2?&62

$aq& >+$aq& -3u$>+&$>2?&52

$aq& >2?$& D1 1.11:mol%1dm+

-3u$>+&$>2?&52

$aq& >+$aq& -3u$>+&2$>2?&2

$aq& >2?$& D2 +.161:+mol%1dm+

-3u$>+&2$>2?&2$aq& >+$aq& -3u$>+&+$>2?&+2$aq& >2?$& D+ 7.771:2mol%1dm+

-3u$>+&+$>2?&+2

$aq& >+$aq& -3u$>+&$>2?&22

$aq& >2?$& D 1.+51:2mol%1dm+

D1, D2, D+, Dare called stepwise sta!ility constant

he eHuili!rium constant of o;erall reaction0

[ ][ ] 9+219+2

62

2

229+ DDDD5>.?&-3u$>

.?&$>&-3u$5>D ==

+

+

D is called the sta!ility constant of the comple# and it gi;es a measure of the sta!ility

of the comple# ion

he comple#es with large sta!ility constant is sta!le

"tereostructure: he spatial arrangement of ligands around the central metal is related to the coordination num!er

he coord. no. is determined !y0 'i)e of the central metalo. and nature of ;acant or!itals for forming dati;e !onds

+&2and -3o3l

2%

few fourcoordinated comple#es are ha;ing sHuare planar structure0

"#ample0 -3u$>+&2and -3u3l

2%

he -3u$>+&2and -3u3l

2%comple# should !e si#coordinated and in octahedral

structure, !ut the two >2? is loosely !onded and ignored usually

@somerism occurs in the comple#es0

'tructural isomers0 Bifferent ligands coordinated to the central metal


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"#ample0 -3o$>+&5=r2'?

2%and -3o$>+&5'?=r%


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?ctahedral comple#es0

-4a!20 4

!a

!a

a

a

and 4

aa

!a

!

a

-4a+!+0 4

!a

!a

!

a

and 4

aa

!a

!

!

Catalysis$atalytic action: d=loc elements and their cpds are common catalysts in industry ( !iological systems

=y pro;iding suita!le reaction surfaces, or

=y forming unsta!le intermediates

3ommon catalysts0

2?5or ?+%0 3ontact process, 2'?2$g& ?2$g& +'?+$g&

e or e2?+0 >a!er process, 2$g& +>2$g& 2>+$g&

4n?20 Becomposition of hydrogen pero#ide, 2>2?2$&2>2?$& ?2$g&

i0 4anufacture of margarine, E3>3>2 2>2$g&E3>23>+

Pt0 4anufacture of nitric$& acid, >+$g& 5?2$g&?$g& 6>2?$&

Heterogeneous catalysis: @n heterogeneous catalysis, the catalyst and reactants are in different phases

Lsually, the catalyst are finely di;ided solids

he heterogeneous catalyst pro;ides a suita!le reaction surface for reactants to come closetogether and react

"#ample, catalysis of gaseous reaction on solid surfaces lie >a!er process

?utlined mechanism0

he gaseous reactant diffuse to the catalyst

he catalytic surface adsor!s one reactant $3at E13at%E1&

he catalytic surface adsor!s another reactant $3at E23at%E2&=ond !reaing ( forming !tw catalyst ( reactants $3at%E1 3at%E23at%E2%E1%3at&

he products desor!ed and diffused away $3at%E2%E1%3at E1%E2&

he a!undance of ;alence e%and a;aila!ility of ;acant or!itals in d!loc elements facilitate the

surface adsorption of reactants

he adsorption !rought the reactants within close pro#imity to cataly)e reaction

Homogeneous catalysis: @n homogeneous catalysis, the catalyst and reactants are in same phase

he catalyst form an intermediate with the reactants to cataly)e reaction

Eeaction mechanism is changed such that "is lower

"#ample0 '2?82%

$aq& 2@%

$aq&2'?2%

$aq& @2$aq& is slow due to inetic factors

e+can cataly)e the reaction as e2$aq& e% e2$aq&0

2@%$aq& 2e+

$aq& @2$aq& 2e2

$aq&

2e2$aq& '2?82%

$aq& 2'?2%

$aq& 2e+

$aq&

e+o#idi)es iodide ions and gi;es e2, !ut e2reduces pero#odisulphate$@& and gi;es e+

he catalyst is unchanged at last

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