Chemical bonding
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This document summarizes the different types of chemical bonding: ionic bonding occurs between oppositely charged ions and is electrostatic in nature; covalent bonding involves sharing electrons between atoms and can range from partially ionic to completely covalent; metallic bonding is characterized by positive ions floating in a "sea" of delocalized electrons allowing metals to conduct electricity; van der Waals bonding is the weakest type and only present between inert gases due to induced dipole interactions. The document also discusses the different arrangements of spheres to model ion packing in cubic close, body-centered cubic, and hexagonal close packing of metals.
Chemical bonding
- 2. CONTENT • INTRODUCTION • DIFFERENT TYPES OF BONDING 1. IONIC BONDING OR POLAR BONDING 2. COVALENT BONDING OR HOMOPOLAR BONDING 3. METALLIC BONDING 4. RESIDUAL BONDING OR VANDER WALLS BONDING • CONCLUSION • REFERENCE
- 3. INTRODUCTION The structural principle in crystals there are two aspects to be discussed The geometry of the molecular arrangement The thermo dynamic factor which decides such arrangement The second aspect is related to the nature of chemical bonding these are four type of bond namely:- • Ionic bond •Covalent bond •Metallic bond •Vander walls bond
- 4. IONIC BONDING • Negatively and positively charged particles attract each other. • In atoms positive charged particles(protons)attract negatively charged particles (electrons) • Positively charged cations attract negatively charged anions producing ionic bonds in minerals • The bond elements together to form compounds, all are electrical.
- 6. COVALENT BONDS • Giving up or gaining electrons to become ions, atoms may become stabilized by sharing electrons • The sharing of electron between the atom is known as covalent bonds • If the sharing is complete the bond is 100% covalent. • Covalent bonds are strong bonds • Example Diamond,pure Carbon
- 8. METALLIC BOND • Metals hold on to their valence electrons very weakly. • positive ions (cations) floating in a sea of electrons. • Electrons are free to move through the solid. • Metals conduct electricity. • Crystals with this type of bonding are called metallic crystals • Some metallic elements atomic structure is more complex, with more than one type of bond occuring between the atoms
- 9. Cont.……… • Three ways in which the ions of most metals are packed together to form crystals • Three method of stacking spheres of equal size cubic close packing Body centered cubic close packing Hexagonal close packing
- 10. CUBIC CLOSE PACKING • Sphere represent identical metallic ions • Each sphere touches three in the layer above or below • A succession of three layer can be placed one on top of the other in different positions • The fourth layer repeats the position of the first • The patterns repeats after every third layer
- 12. BODY CENTRED CUBIC PACKING • Sphere represent identical metallic ions • Spheres lie at the corners of cube and with one sphere at the center of each cube • Each sphere touches eight others ,and the packing is not as close as in the other two types • Close packed layers are absent • Metal with this type of structure is harder and more brittle • Iron has this structure at normal temperature. • High temperature it posses the cubic close packed structure and consequence, become malleable.
- 14. HEXAGONAL CLOSE PACKING • This structure contain close packed layers with the canters of identical sphere laying at the corners equilateral triangle • Adjoining layers are displayed so that any sphere lies above or below three spheres in the layer next in to it, with every alternate layer identical. • The structure repeats after every second layer instead of after every third as in the cubic close packing.
- 16. VANDER WALLS BONDING • It is weak force of attraction between the ions or atoms of all solids. • Bond is differs from the all the others in that, it is rarely responsible for the coherence of any common substance . • Residual bond effect is often masked in structure, where ionic covalent or metallic bonding already occurs. • The only solid entirely with Vander walls bonding are inert gases(neon ,argon,etc) in the solid state.
- 17. • A chemical bond is an attraction between atoms that allows the formation of chemical substances that contain two or more atoms. The bond is caused by the electromagnetic force. • In general, strong chemical bonding is associated with the sharing or transfer of electros between the participating atoms. CONCLUSION
- 18. REFERENCE • Books • Jak tareen & TRN kutty:2011 A basic course in crystallography University press (India) limited • Rutley‘s text book of mineralogy • website • F:Chemical bond - Wikipedia, the free encyclopedia.mht