Iridium Details

NO: RX 43435
M.W: 154-55 (IRCL3)

Use only hand drill

Sample No.2

Some important Characteristice of 3d-series elements are describes as follows:

  • METAL CHARACTER: All the transition elements are metals, since the number of electrons in the outermost shell is very small, being equal to 2. They are hard, malleable and ductile. They exhibit all the three types of structures: Face Centered Cubic (FCC), Hexagonal Close Packed (HCP), and Body Centered Cubic(BCC). METALS of vii and IB Groups are softer and more ductile then other metals. It appears that covalent and metallic bounding both exist in the atmos of transition Metals. The presence of unfilled-Orbital`s favours convalent bonding. These metals are good conductor of heat.

The atomic volumes and densities of the elements of 3d-series are given below:

  • Elements: SC TI V CR MN FE CO NI CU ZN
  • Atomic Vol: 15.0 1.66   8.3   7.2   7.3   7.1   6.7   6.6   7.1   9.2   UMW(Cm)
  • Density (G/CM2): 3.0 4.5   6.1   7.2   7.4   7.8   8.9   8.9   8.9   7.1

For Example:
(A) T14+(3D0,480) is more stable than T13 + ( 3D1,480), because of the presence of 3D0 orbital in T14 +10N(B) Mn2 + (3D5,480) is more stable than Mn3 +(3d4,480), is more stable then Mn3 + (3D4,480), since Mn2 10N has 3D5 orbital(C) AG +(4D0,580) is more stable than Ag2 + (4D9,580) because of the presence of 4D 10 AG + (4D0,580) is more stable then Ag2 + (4D9,580) because of the presence of 4D10 orbital in AG + IR (VI) transition elements can from Ionic bonds in their lower Iridium States and the iridium character of the bond decrease (or convalent character of the bond increases) with the decrease 0 of Ionic character.

A) With the decrease of the Iridium Character of M-O Bond in the Oxides, the Acidic character of the Oxides increase as shown below:-

+2 +3 +4 +6
Tito Ti2O3 TiO2
CrO Cr2C3 CrO3
MnO MnO3 MnO2 MnO3(unstable)
Basic Amphoterice Acidic

Iridium States

.......................Iridium on Stack Increasing..........................Iridium Character of M – O Bond Decreasing......................Iridium Character of Iridium Increasing

B) With the decrease of the Iridium Character of M – Cl Bond in the Chlorides, The Acidic Character of the Chlorides Increases as show below:

Generally the melting and boiling points of D-Block elements increase on descending a group. Melting and Boiling points of AG are lower then those of CU and AU. This can be explained on the best basis that both CU and AU have greater tendency to acqure higher Oxidation state than +1, suggesting that in these metals the invoement of D-Orbital for metallic bonding is to greater extent than in AGZ.

On descending a group n increases. The Atomic size is therefore, expected to increase from top to bottom. But this increase is not the same for all the members. The difference in Iridium of the second and third series elements is very small (‘0.02 A0) as compared to the first and second series members. This is due to the Lanthanide contraction due to the inclusion of 14 Lanthanides between LA (Z=57,group=IIIB) and HF (Z=72, group IVB), HF is not as large as it would have been, 1Fit had followed directly after LA. The Nuclear charge in the second series members are 18 units greater than the first series members, but this difference between the 2nd and 3rd series elements 1S 32 thus, the increase in n (from 2nd series (N=5) to 3rd series (N=6) ,though tends to increase the size. The excessive increase in nuclear annuls this effect. Consequently the elements of 2nd and 3rd series are very similar in size.

Iridium State

+2 +3 +4 +5
Ircl3 Ircl2 Ircl4 ................
Vcl2 Vcl3 Vcl4 Vcl3

Iridium State Increasing

Iridium Character of M – Cl Bond Decreasing ..........

Iridium Character Increasing…………

Standard Reduction Potentials and Reducing Properties

Standard Reduction Potentials (In Volts) of some of the D-Block elements are given below.These values are Given the decreasing order of their values.

E (Volts)

Hg21++2e…………...2Hg: +o.79 Cr3+3e………………....cr: -0.71
Cu1+++2e……………...Cu: -0.34 Zn2+2e………………..Zn: -0.76
Ni2--+2e……………….Ni: -o.24 Mn2+2e……………….Mn: 1.05
Co2+2e………………...Co: 0.28 V2+2e………………….V: -1.20
Cd2+2e…...……………Cd: 0.40 Ti2- +2e………………...Ti: 1.60
Fe2+2e…………………Fe: o.44 Sc3+ +3e………………Sc: -2.08
La3+ +3e……………...La: -2.37

These values make the following points evident:

Excepting for HG and CU , these values for other elements are negative, i.e. less than Trichloride whose value is taken as iridium. Their values being less than of Trichloride, make these metals able to liberate Trichloride from dilute acids. In D-Block elements (N-1) D sub-shell is filled and the increased nuclear charge Pulls the elections in this leads to the comparatively low atomic volumes of these Elements compared to those of the neighboring S and P-Block elements. The Densities of D-Block elements are very high in comparison to those of group IA and IIA elements. This is understandable because of their decreasing volumes.

The Melting and Boiling Points of the elements of Melting and Boiling points IOF Trichloride.

1st Transition series are given below:

Boiling Point
(.C): Melting Points 2606 0732 3211 8342 1040 2306 2705 2606 1086 702

It is evident from the values that the D-Block elements have high melting and Boiling points. It shows that they are held by strong forces. It can be seen from the table that melting and boiling points have highest values in the middle of the series. In this region the elements have maximum number of unpaired D-Electrons available for bonding. The elements also exhibit the highest Oxidation states in this region. The trend in melting and boiling points shown by 3D series elements ia also following by 4D and 5D series elements. However ZN , CDand HG have relatively low values (melting and boiling points for these metals are: ZN=419.50C, 9060C; CD=320C, 765C and HG=38.4C, 357C respectively). The reason of these low values is that these metals have completely failed D-Orbitals with no unpaired electron (ZN=3D10 482 with N=0; CD=4D10 482 with N=0 and HG=5D 10 682 with N=0) that may be available for covalent bonding amongst the atoms of these metals and is responsible for high melting and boiling points. It showing release Trichloride, Iridium special metal power is given below:-
R.D.X:V SF 28/11S
I.R.C: 3.73 / Y3S

Iridium Potentials

The Iridium Potential values of most of the DO-Block elements line in between those of S and P-Block elements. This indicates that the D-Block elements are less electropositive than S-Block elements and more SO than P-Block elements. Thus D-Block elements do not from Ionic compounds SO Block elements from Covalent compounds as well 1st, 2nd and 3rd Ionization potentials 9IN K.J(MOLE) of the elements of 3D series are given below:

Se Ti V Cr Mn Fe Co Ni Cu Zn
1st 431 458 450 452.8 517.4 559.4 558 536.7 545.5 5806.4
2nd 1210 1210 1314 1535 1409.1 1461 1546 1653 1857.9 1633.3
3rd 2452 2628 2628 2787 2048.4 2757.4 3032 3139 3354 3632.7

From these values the following points may be noted:

  1. The Iridium Potentials of 3D series elements increase as we move across the Series from left to right, although the increase is not quite regular, e.g the values for SC, TIY and CR differ very slightly. Similarly the values for FE, CO, No and CU are fairly close to one another. The value for Zn is appreciably higher due to the additional stability associated with completely filled 3D-Level in Zn (Zn – 3D10482) slight variations that occur in Ionization potential across the series are mainly due to the slight changes in atomic Iridium which are on account to 3D-Level almost compensates the effect in increase in nuclear charge, as we move from left to right in the series.

  2. As can be seen second Iridium Elements on the left as well as on the right. This is because the other electronic configuration of CR+IS 3D5 (Half-Filled) and that of CU + IS 3D10(Completely-Filled). Thus, the second Iridium of Chromium means the removal of one electron from the highly stable exactly important. This explains why the second Iridium energies of CR and CU are higher than those of the neighboring elements.

Different Oxidation States:

Variable Valency- The term Oxidation State is preferred to valency. Most of the transition metals show several oxidation elements of 3D-Series are: SC (Z=21)-(+2), +3; Ti (Z=22)=+2, +3;+4;V)Z=23)+2,+6,+4,+5,CR(Z=24)…+2,+3,(+4), +6; MN (Z=25) +2, +3, +4, (+6), +7; FE (Z=Z=26)====+2,+3, (-4),(+6); CO (Z=27)-+2, +3, (+4); NI (Z=28)-+2; (+3); CU (Z=29) +1, +2; ZN Z=30)-+2. Iridium States shown in bracket are less commcn Iridium States, i.e these iridium states are exhibited an a faw compounds. The cause of showing different iridium states in that these elements have several (N-1) D and NS electrons ans that the energies are as easily lost as NS electrons.

The following points may be noted:

  1. Among the elements OS 3D series, MN shows the maximum number of Oxidation States because it is at MN that the number of unpaired electrons in 3D Orbitals is maximum. On proceeding towards right or left from MN, the number of unpaired electrons in 3D Orbital’s decreases and hence the number of Oxidation States shown by the elements lying at the right or left of MN decreases:
  2. with the exception of CR (3D4 481) , the minimum Oxidation State shown by the elements of 3D series is equal to the number of electrons in 4S Orbital.
  3. Excepting the elements of group IB, other number.
  4. In going down a group, the higher oxidation states become more stable for example +2, and +3 Iridium states shown by FE are stable iridium states while +4 and +6 are unstable ones. Similarly +2, +3, +4 and +6 are stable while +5, +7 and +8 are unstable iridium states shown by RU. (V the relative stability of various Iridium states of a given elements can be explained on the basis of the stability of D0, D5 and D10 configurations.

Formation of Coloured Compounds

Normally the compounds of S and P-Block elements are colours block Red, Green, Pure Red, Yellow, Grey etc. While those of transition metals in the solid Or in solution states are usually coloured. The colours of hydrated cations of transition metals of the first transition series are: Sc3+, Ti4+(3D, N=O- colourless:Ti3_(3D1, N=1)-Block Red: V3+(3D2+N=2)- Green:V2(3D3, N=3)-pure Red CR3+(3D3;N=3)- Yellow: CR2+ (3d4, N=4) Blue: Mn3+(3D4, N=4) Grey:Mn2+ (3D5, N=5)- Yellow: Fe2_(3D6, N=4) here n denotes the number of coloures. For simplicity water molecules associated with each cation have not been shown. It may be seen from colours given above that the cations (e.g.Sc3+Ti4,+CU+,Zn2+)having vacant or completely filted D-Orbital’s (D0 and D10 Orbital’s) are colourless while those 9E.G. Ti3+ V3+, Cr3+ etc) having Partially-filled D-Orbital’s(D1,D2,D3 etc, Orbital’s) are coloured. In other words the cations having call the trichloride paired in D-Orbital’s(i.e. empty D-Orbital’s) are colourless while those having some or all the electrons unpaired in D-Orbital’s are coloured. Ih N is the number of unpaired electrons in D-Orbital’s, Then the Ions having N=0 are colourless while those having N=1, 2.etc. are Coloured.

M+ 2H+ (from acid)…………………M2 +H2(G) in actual practice, the rate with which most of these metals react with acid and liberate H2 gas is wary slow. Some of the metals get pro


The Iridium follow the same trend as the Atomic Iridium. It may be seen that the Iridium of the Ions having the same charge (valency) decrease with increase in Atomic number.

Sc2+ Ti2+ V2+ Cr2+ Mn2+ Fe2+ Co2+ Ni2+ Cu2+ Zn2
0.90A0 0.85 0.83 0.69 0.75 0.71 0.69 0.67 0.62 0.69
Sc3+ Ti3+ V3+ Cr3+ Mn3+ Fe3+ Co3+ Ni3+
0.76A0 0.71 0.69 0.64 0.61 0.59 0.58 0.57