Chemestry, element-Zr, Zirconium
Zirconium
Zirconium (assigned the symbol Zr , a chemical element with the atomic number of 40 , is a transition metal element found in Group IVa of the periodic table
Zirconium is a rare light-grayish lustrous metal . It is corrosion-resistant because it forms an oxide film on its surface which inhibits further corrosion . It is also highly resistant to heat . It is a strong metal , and has a hardness similar to that of copper , but is lighter than steel . It is also highly malleable and ductile . It is rarely found in its pure [banner_entry_middle]
form because of its high reactivity to oxygen nitrogen , carbon , and silicon
Atomic structure
Number of Energy Levels 5
First Energy Level 2 Second Energy Level 8
Third Energy Level 18
Fourth Energy Level 10
Fifth Energy Level 2
Electron Configuration 1s2
2s2p6 3s2p6d10 4s2p6d2 5s2
Valance Electrons 4d2
5s2
Number of Electrons (with no charge ) 40
Number of Neutrons (most common /stable nuclide : 51
Number of Protons 40 Figure 1 . Shell Model (Yinon
Figure 2 . Electron Dot Model
Figure 3 . Crystal Structure
Atomic Radius : 2 .16E
Atomic Volume : 14 .1cm3 /mol
Covalent Radius : 1 .45E
Crystal Structure : Hexagonal
Filling Orbital : 4d2
Ionic Radius : 0 .72E
Ionization Energy : 6 .634 eV
Number of Stable Isotopes : 4
Oxidation States 4
Estimated Crustal Abundance : 1 .65CH102 milligrams per kilogram
Estimated Oceanic Abundance : 3CH10-5 milligrams per liter
Estimated Abundance in the Sun 560 milligrams per liter (Relative to H 1E12
PHYSICAL PROPERTIES OF ZIRCONIUM
Physical Properties
Atomic Mass Average 91 .224
Boiling Point 4650K 4377 ?C 7911 ?F Coefficient of lineal thermal expansion /K-1 5 .78E-6
Conductivity Electrical 0 .0236 106 /cm
Thermal 0 .227 W /cmK
Density 6 .51g /cc 300K
Elastic Modulus Bulk 89 .8 /GPa
Rigidity 35 /GPa
Youngs 98 /GPa
Enthalpy Atomization 598 kJ /mole 25 ?C
Fusion 20 .9 kJ /mole
Vaporization 581 .6 kJ /mole
Flammablity Class Combustible
Freezing Point (see melting point
Hardness Scale Brinell 650 MN m-2
Mohs 5
Vickers 903 MN m-2
Heat of Vaporization 58 .2kJ /mol
Melting Point 2125K 1852 ?C 3366 ?F
Molar Volume 14 .06 cm3 /mole
Physical State (at 20 ?C 1atm : Solid Specific Heat 0 .27J /gK
Vapor Pressure 0 .00168Pa 1852 ?C CHEMICAL PROPERTIES OF ZIRCONIUM
Zirconium is difficult to separate from hafnium using chemical means since it does not dissolve in alkalis and acids . It is similar to silicon in its chemical properties
Reaction with air . In its solid state , zirconium is relatively stable although it can spontaneously ignite with air at high temperatures when finely divided
Zr (s O2 (g ? ZrO2 (s
Reaction with halogens . At elevated temperatures , zirconium reacts halogens to form zirconium (IV ) halides
Zr (s 2F2 (g ? ZrF4 (s ) [white]
Zr (s 2Cl2 (g ? ZrCl4 (l ) [white]
Zr (s 2Br2 (g ? ZrBr4 (s ) [white]
Zr (s 2I2 (g ? ZrI4 (s ) [white]
Chemical Properties
Electrochemical Equivalent 0 .8509g /amp-hr Electron Work Function 4 .05eV
Electronegativity 1 .33 (Pauling 1 .22 (Allrod Rochow
Heat of Fusion 16 .9kJ /mol
Incompatibilities Potassium nitrate , oxidizers… [banner_entry_footer]
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