Type of bonds. Four general categories bonds 2. ionic 3. covalent 4. Vander Waals
|
|
- Amice Reeves
- 5 years ago
- Views:
Transcription
1 Type of bonds Four general categories bonds 1.metallic 2. ionic 3. covalent 4. Vander Waals Primary bond is commonly applied to metallic type. ionic covalent ~100 kcal/mol Secondary bonds : Vander Waals ~ <10 kcal/mol There is almost more than one type of bond in a ceramic solid ( ionic + covalent). 1
2 The metallic bond is equally effective in all three coordinate directions. The coulombic attractions of the ionic bond is also equally effective in all three coordinate directions. The covalent bond is very specifically oriented and is most effective between the two atoms of a pair. The Vander Waals bonds, although weak, are polar and therefore directional. Metalic : Positive ionic are held together by free electrons. Ionic : Positive and negative ions are held together by coulomic attraction. Covalent : Electrons are shared with electron pairs between two positive ions. Vander Waals : The centers of positive and negative charges are not coincident. Therefore an apparent coulombic attraction exist. 2
3 Ionic bond Materials which derive most of their coherency from coulombic forces of attraction betwee n charged atoms are classified as ionic solids. The net coulombic attraction within an ionic solid. As the positive and negative ions are brought closer together, energy is release. Not until the electron shells around the ions begin to interact are the net coulombic forces of attraction balanced by those of repulsion. (1) Coulombic energy The potential energy E, corresponding to two point charges. : the distance between two points : no. of charges at each point. e : coul 3
4 All scientific evidence indicates that the lowest energy condition is the most stable. This factor is responsible for the natural tendency of atoms to assume positions in which there is a min. of free energy. The grouping of atoms in close coordination are due to the attractive repulsive forces between atoms. The equilibrium spacing between atoms is that distance at which the attractive and repulsive force are balanced. (i) Unlike charges give a negative value to E, indicating that energy is given off as the distance is decreased. (when two unlike, monovalent ions are closed) (ii) The energy of two positive ( or two negative ) monovalent ions increases as these are brought closer together. 4
5 (2) Madelung constant The Madelung constant is the ratio of the potential energy of an ion within a three-dimensional solid to the energy between a single pair of ions. Ex. NaCl The removal of a sodium ion from the interior of a NaCl crystal requires times as much energy as it does to separate it from a single ion. Ex. Calculate the Madelung constant for a hypothetical linear array of alternating positive and negative monovalent ions. Ans : 5
6 (3) Electronic repulsion energy This repulsive energy between the electron shells of adjacent atoms may be expressed by b : constant n : ~9 as determined expertimentally The sum U of the net coulombic attractive and electron repulsive energies is E C + E R. At the interatomic distance a,, ( one monovalent ion within an ionic crystal ) The energy per mol, Since n 9, U = 184 kcal/gm-mole for NaCl is exceedingly close to the experimental value of kcal/gm-mole. 6
7 Covalent bonds This type of bond involves mutual sharing of two electrons by adjacent atoms and is frequently encountered in ceramic materials. Useful qualitative relationship : (1) A covalent bond always involves two electrons. (2) The no. of covalent bonds, N is 8-V, where V is the no. of valence electrons. (3) No more then four covalent bonds. (4) Single, double, and triple bonds are possible, involving two, four, and six electrons between an adjacent pair of atoms. Covalent bonds can be very strong. Evidence of this is found in diamond and in refractory and abrasive ceramic compounds which depend extensively on covalent bonding. Polyatomic group-covalent bonds are associated almost exclusively with the semimetallic and nonmetallic atoms which are located in the upper right-hand corner of the periodic table. Since these elements can share electrons, it is not surprising to find them clustering into larger polyatomic units. Polyatomic groupings may be formed which do not have enough electrons to fill the outer-shell requirement. Such units become more stable if they receive additional electrons from external sources. When this occurs, the unit become a polyatomic anion as shown in Fig
8 8
9 Vander Waals bonds These bonds originate through electrical dipole inside the materials. With the displaced center of charge, the positive end of one dipole can be attracted to the negative end of another dipole. Vander Waals bonds are also evident in compounds that form true molecules, such as, H 2 O, SiF 4, CO 2, they have strong intramolecular forces, but only weak intermolecular attraction; therefore these compounds liquefy and gasify as independent molecules. Dipoles may be induced by an electric field applied. In ceramic material, there are two main structural and behavioral consequences of the Vander Waals force of attraction : (1) they serve as the loci for plastic slip (e.g. in clays) and (2) they serve to promote physical adsorption of atoms, ions or molecules onto solid and liquid surfaces. 9
10 It should be noted, however, that neighboring atoms or ions may induce distortion in any particular dipole ; therefore a precise calculation is not always possible. 10
11 Ex. The H-N-H bond angle in ammonia is 112, and the H-N couple has a dipole moment of 1.7 debyes, what is the dipole moment of NH3? Ans: V : the vertical compound h : the horizontal compound sin 56 x 1.7, sin 60 x h h 1.7 sin sin 60 v (1.7)2 (1.63)2 0.5 dipole moment of NH3 = 3V = 1.5 debyes 11
12 Stability of ionic crystal structures The Madelung constant The Madelung constant is a precise definition of the energy of a particular crystal structure relative to the same no. of isolated molecules Ex. KCl K Cl e K e Cl expenditure of 4.34 ev Ionization energy an energy gain of 3.82 ev Electron affinity The energy for ionic bond between a cation and anion pair can be described by two terms : (1) coulombic attraction the basis for the bond. (2) repulsion due to the pauli exclusion principle that becomes strong at very close separation. Electrostatic energy : the permittivity of free space : an empirical constant : the interatomic separation 12
13 R 0 = R A + R C, at which the total energy is minimum, which we will denote as E 0. a crystal composed of N molecules the energy of whole NE 0. rewrite : cation valence : anion valence 13
14 α : the summation of the electrostatic interaction Madelung Constant : Represents the electrostatic energy of the crystal relative to the energy of the same no. of isolated molecules. C : the sum of the short-range repulsive interaction. The Madelung Constant is a measure of the magnitude of the electrostatic stabilization, and for stable crystals has a value > 1. 14
15 It can be seen that the differences between some structures are relatively small. Zincblend the difference in electrostatic energy is Wurtzite minor (~0.2%). When the energy difference between different structure types of the same stoichiometry (polymorphism) is small. For ionic crystals the majority of the interaction energy lies in the electrostatic term, with the short-range repulsion accounting for only about 10% of the interaction. ~10 ~10%, n n n e Z Z N E C e Z Z N Ec R e Z Z C R R R E A C C A C n A C C 15
16 Ceramics Inorganic and nonmetallic materials Compounds between metallic and nonmetallic elements Bonding: ionic or ionic + covalent Ceramic 由希臘字 Keramikos 而來, 意謂 burnt stuff, 係指經高溫燃燒處理所得的材料 傳統陶瓷 精密陶瓷 16
17 Crystal Structure of Ceramics Atomic bonding: Ionic 離子鍵比例 Cations ( 陽離子 ) Anions ( 陰離子 ) 影響陶瓷結構的因素 : 電荷 離子半徑 電荷 : 維持電中性, CaF 2 離子半徑 :r c, r A, r c < r A, r c / r A < 1 每一陽離子欲最大量陰離子於周圍 每一陰離子欲最大量陽離子於周圍 17
18 Crystal Structure of Ceramics Stable structure: 圍繞於陽離子周圍的陰離子都與陽離子接觸 Coordination Number(CN ; 配位數 ): 最靠近陽離子的陰離子總數, 與 r c / r A 比值有關 Critical or minimum r c / r A ratio => 特定 r c / r A 比 Bond strength ( 鍵結強度 ) = 電荷 ( 陽離子 )/CN 18
19 19
20 離子半徑 20
21 Crystal Structure v.s. Close Packing of Anions B layer of close-packed oxygen atoms is positioned with respect to the A layer. The two are identical except for a lateral translation. The B-layer atoms do not lie directly above any of the A-layer atoms. 21
22 22
23 23
24 Crystal Structure v.s. Close Packing of Anions Atomic close packing: FCC, HCP Stacking close-packed planes of large anions => unit cell => Two interstitial sites: Tetrahedral (T) sites => CN No.= 4 Octahedral (O) sites => CN No.= 6 24
25 Octahedral site : atoms =1:1 Tetrahedral site : atoms =2:1 25
26 Crystal Structure v.s. Close Packing of Anions For each of anion spheres => one Octa. position and two Tetra. position exist. Consider two factors FCC (ABCABCA..) or HCP (ABABA.) Cations put in Tetra. sites or Octa. sites NaCl => FCC stacking => Na in Octa. sites (CN=6), fill in all Octa. sites Spinel structure 尖晶石結構, AB 2 O 4, e.g. MgAl 2 O 4 => O in FCC stacking, Mg in Tetra. sites, Al in Octa. sites. 26
27 Pauling s rules : (1) Based on the geometric stability of packing for ions of different size. (2) Simple electrostatic stable argument. Rule 1. Each cation will be coordinated by a polyhedron of anions, the no. of ions in which is determined by the relative sizes of the cation and anion. Rule 2. This rule ensures that the basic coordination polyhedra are arranged in three dimensions in a way that preserve local charge neutrality. Bond strength = Ex. MgO : Octahedrally coordination Mg 2+ have bond strength of 2/6. This is qualitatively a measure of the relative fraction of the 2+ charge that is being allocated to or shared with each of the coordinating anions. The coordination of cations around anions as well as those of anions around cations. Rule 3. Coordination polyhedra prefer linkages where they share corners rather than edges, and edges rather than faces. This rule is simply based on the fact that cations prefer to maximize their distance from other cations in order to minimize electrostatic repulsion. 27
28 28
29 Rule 4. When C.N. is small or the cation valence is high, that rule 3 becomes more important. This also is based on electrostatic. Rule 5. Simple structure are usually preferred over more complicated arrangement. Summary Ex. MO has, Case 1. If octahedral coordination (C.N.= 6) is preferable, all of octahedral sites will be filled, since octahedral sites atoms Case 2. If tetrahedral coordination (C.N.= 4) is preferred, only ½ tetrahedral sites need be filled, since These sites will tend to be filled in a way that maximizes the cation separation, according to Pauling s 3 rd and 4 th rules. tetrahedral sites atoms
30 30
31 AX-type Crystal Structure Rock Salt structure 食鹽結構 NaCl, MgO, MnS, LiF, FeO 雙面心結構 31
32 AX-type Crystal Structure Cesium Chloride Structure CsCl CN No.=8 for each Cs Not BCC Simple cubic 32
33 AX-type Crystal Structure Zinc Blende 硫化鋅 structure ZnS, ZnTe, SiC ZnS CN No. = 4 S: FCC sites Zn: half filled Tetra sites Highly covalent 33
34 A m X p -type Crystal Structure Charges of cations and anions are different CaF 2, UO 2,PuO 2, ThO 2 E.g. fluorite structure 氟石結構 ;AX 2 ; CaF 2 ; rc/ ra = 0.8 => CN = 8 Ca 離子數量是 F 離子之一半 34
35 A m B n X p -type Crystal Structure Perovskite crystal structure 鈣鈦礦結構 Two types of cations BaTiO 3 T > 120 o C, cubic 35
36 36
37 37
Type of bonds. Four general categories bonds 2. ionic 3. covalent 4. Vander Waals
Type of bonds Four general categories bonds 1.metallic 2. ionic 3. covalent 4. Vander Waals Primary bond is commonly applied to metallic type. ionic covalent ~100 kcal/mol Secondary bonds : Vander Waals
More informationAtomic Arrangement. Primer in Materials Spring
Atomic Arrangement Primer in Materials Spring 2017 30.4.2017 1 Levels of atomic arrangements No order In gases, for example the atoms have no order, they are randomly distributed filling the volume to
More informationChapter 3. The structure of crystalline solids 3.1. Crystal structures
Chapter 3. The structure of crystalline solids 3.1. Crystal structures 3.1.1. Fundamental concepts 3.1.2. Unit cells 3.1.3. Metallic crystal structures 3.1.4. Ceramic crystal structures 3.1.5. Silicate
More informationIonic Bonding. Chem
Whereas the term covalent implies sharing of electrons between atoms, the term ionic indicates that electrons are taken from one atom by another. The nature of ionic bonding is very different than that
More informationAtomic Arrangement. Primer Materials For Science Teaching Spring
Atomic Arrangement Primer Materials For Science Teaching Spring 2016 31.3.2015 Levels of atomic arrangements No order In gases, for example the atoms have no order, they are randomly distributed filling
More informationChapter 12: Structures & Properties of Ceramics
Chapter 12: Structures & Properties of Ceramics ISSUES TO ADDRESS... Bonding and structure of ceramic materials as compared with metals Chapter 12-1 Atomic Bonding in Ceramics Bonding: -- Can be ionic
More informationCeramic Bonding. CaF 2 : large SiC: small
Recall ceramic bonding: - Mixed ionic and covalent. - % ionic character ( f ) increases with difference in electronegativity Large vs small ionic bond character: Ceramic Bonding CaF : large SiC: small
More informationChapter 12: Structures of Ceramics
Chapter 12: Structures of Ceramics Outline Introduction Crystal structures Ceramic structure AX-type crystal structures A m X p -type A m B n X p - type Silicate ceramics Carbon Chapter 12 - Ceramics Two
More informationPY2N20 Material Properties and Phase Diagrams
PY2N20 Material Properties and Phase Diagrams Lecture 10 P. Stamenov, PhD School of Physics, TCD PY2N20-10 Modern CMOS pair structure Photolithographic Process CMOS Processing Steps Cu Damascene Process
More informationSOLID STATE CHEMISTRY
SOLID STATE CHEMISTRY Crystal Structure Solids are divided into 2 categories: I. Crystalline possesses rigid and long-range order; its atoms, molecules or ions occupy specific positions, e.g. ice II. Amorphous
More informationMetallic & Ionic Solids. Crystal Lattices. Properties of Solids. Network Solids. Types of Solids. Chapter 13 Solids. Chapter 13
1 Metallic & Ionic Solids Chapter 13 The Chemistry of Solids Jeffrey Mack California State University, Sacramento Crystal Lattices Properties of Solids Regular 3-D arrangements of equivalent LATTICE POINTS
More informationLattice energy of ionic solids
1 Lattice energy of ionic solids Interatomic Forces Solids are aggregates of atoms, ions or molecules. The bonding between these particles may be understood in terms of forces that play between them. Attractive
More informationInorganic Chemistry I (CH331) Solid-state Chemistry I (Crystal structure) Nattapol Laorodphan (Chulabhorn Building, 4 th Floor)
Inorganic Chemistry I (CH331) Solid-state Chemistry I (Crystal structure) Nattapol Laorodphan (Chulabhorn Building, 4 th Floor) 7/2013 N.Laorodphan 1 Text books : 1. D.F. Sheiver, P.W. Atkins & C.H. Langford
More informationMetallic and Ionic Structures and Bonding
Metallic and Ionic Structures and Bonding Ionic compounds are formed between elements having an electronegativity difference of about 2.0 or greater. Simple ionic compounds are characterized by high melting
More informationExperiment 7: Understanding Crystal Structures
Experiment 7: Understanding Crystal Structures To do well in this laboratory experiment you need to be familiar with the concepts of lattice, crystal structure, unit cell, coordination number, the different
More informationMetal Structure. Chromium, Iron, Molybdenum, Tungsten Face-centered cubic (FCC)
Metal Structure Atoms held together by metallic bonding Crystalline structures in the solid state, almost without exception BCC, FCC, or HCP unit cells Bodycentered cubic (BCC) Chromium, Iron, Molybdenum,
More informationE12 UNDERSTANDING CRYSTAL STRUCTURES
E1 UNDERSTANDING CRYSTAL STRUCTURES 1 Introduction In this experiment, the structures of many elements and compounds are rationalized using simple packing models. The pre-work revises and extends the material
More informationEarth Solid Earth Rocks Minerals Atoms. How to make a mineral from the start of atoms?
Earth Solid Earth Rocks Minerals Atoms How to make a mineral from the start of atoms? Formation of ions Ions excess or deficit of electrons relative to protons Anions net negative charge Cations net
More informationRemember the purpose of this reading assignment is to prepare you for class. Reading for familiarity not mastery is expected.
Remember the purpose of this reading assignment is to prepare you for class. Reading for familiarity not mastery is expected. After completing this reading assignment and reviewing the intro video you
More informationChapter 12: Structures & Properties of Ceramics
Chapter 12: Structures & Properties of Ceramics ISSUES TO ADDRESS... How do the crystal structures of ceramic materials differ from those for metals? How do point defects in ceramics differ from those
More informationionic solids Ionic Solids
ionic solids Ionic Solids Properties characteristic of ionic solids low conductivity as solids, high when molten high melting points hard brittle solids soluble in polar solvents high melting Hardness
More informationChapter Outline: Ceramics. Chapter 13: Structure and Properties of Ceramics
Chapter Outline: Ceramics Chapter 13: Structure and Properties of Ceramics Crystal Structures Silicate Ceramics Carbon Imperfections in Ceramics Optional reading: 13.6 13.10 University of Virginia, Dept.
More informationSolids. properties & structure
Solids properties & structure Determining Crystal Structure crystalline solids have a very regular geometric arrangement of their particles the arrangement of the particles and distances between them is
More informationBonding and Packing: building crystalline solids
Bonding and Packing: building crystalline solids The major forces of BONDING Gravitational forces: F = G m m 1 2 F = attractive forces between 2 bodies G = universal graviational constant (6.6767 * 10
More informationLecture 04 Structure of Ceramics 1 Ref: Barsoum, Fundamentals of Ceramics, Ch03, McGraw-Hill, 2000.
MME 467 Ceramics for Advanced Applications Lecture 04 Structure of Ceramics 1 Ref: Barsoum, Fundamentals of Ceramics, Ch03, McGraw-Hill, 2000. Prof. A. K. M. Bazlur Rashid Department of MME, BUET, Dhaka
More informationBonding in Chemistry. Chemical Bonds All chemical reactions involve breaking of some bonds and formation of new ones where new products are formed.
CHEMICAL BONDS Atoms or ions are held together in molecules or compounds by chemical bonds. The type and number of electrons in the outer electronic shells of atoms or ions are instrumental in how atoms
More informationChapter 12: Structures & Properties of Ceramics
Chapter 12: Structures & Properties of Ceramics ISSUES TO ADDRESS... Structures of ceramic materials: How do they differ from those of metals? Point defects: How are they different from those in metals?
More informationChem 241. Lecture 20. UMass Amherst Biochemistry... Teaching Initiative
Chem 241 Lecture 20 UMass Amherst Biochemistry... Teaching Initiative Announcement March 26 Second Exam Recap Ellingham Diagram Inorganic Solids Unit Cell Fractional Coordinates Packing... 2 Inorganic
More informationChapter 22 Lecture. Essential University Physics Richard Wolfson 2 nd Edition. Electric Potential 電位 Pearson Education, Inc.
Chapter 22 Lecture Essential University Physics Richard Wolfson 2 nd Edition Electric Potential 電位 Slide 22-1 In this lecture you ll learn 簡介 The concept of electric potential difference 電位差 Including
More informationIonic Bonding. Example: Atomic Radius: Na (r = 0.192nm) Cl (r = 0.099nm) Ionic Radius : Na (r = 0.095nm) Cl (r = 0.181nm)
Ionic Bonding Ion: an atom or molecule that gains or loses electrons (acquires an electrical charge). Atoms form cations (+charge), when they lose electrons, or anions (- charge), when they gain electrons.
More informationChapter 12. Insert picture from First page of chapter. Intermolecular Forces and the Physical Properties of Liquids and Solids
Chapter 12 Insert picture from First page of chapter Intermolecular Forces and the Physical Properties of Liquids and Solids Copyright McGraw-Hill 2009 1 12.1 Intermolecular Forces Intermolecular forces
More informationChapter 11 Intermolecular Forces, Liquids, and Solids
Chapter 11 Intermolecular Forces, Liquids, and Solids Dissolution of an ionic compound States of Matter The fundamental difference between states of matter is the distance between particles. States of
More informationChemistry 121: Topic 4 - Chemical Bonding Topic 4: Chemical Bonding
Topic 4: Chemical Bonding 4.0 Ionic and covalent bonds; Properties of covalent and ionic compounds 4.1 Lewis structures, the octet rule. 4.2 Molecular geometry: the VSEPR approach. Molecular polarity.
More informationBravais Lattice + Basis = Crystal Structure
Bravais Lattice + Basis = Crystal Structure A crystal structure is obtained when identical copies of a basis are located at all of the points of a Bravais lattice. Consider the structure of Cr, a I-cubic
More informationS.No. Crystalline Solids Amorphous solids 1 Regular internal arrangement of irregular internal arrangement of particles
Classification of solids: Crystalline and Amorphous solids: S.No. Crystalline Solids Amorphous solids 1 Regular internal arrangement of irregular internal arrangement of particles particles 2 Sharp melting
More informationStructures of Solids. Unit Cells - Not(?) Chapter 4 Ionic and Other Inorganic Solids. CHEM 462 Wednesday, September 22 T.
Chapter 4 Ionic and Other Inorganic Solids CHEM 462 Wednesday, September 22 T. Hughbanks Structures of Solids Many dense solids are described in terms of packing of atoms or ions. Although these geometric
More informationIntermolecular Forces. Chapter 16 Liquids and Solids. Intermolecular Forces. Intermolecular Forces. Intermolecular Forces. Intermolecular Forces
Big Idea: Systems that form macromolecules (ionic, metallic, and covalent network) have the strongest interactions between formula units. Systems that cannot form macro molecules still contain intermolecular
More informationCeramics Ceramics keramikos - burnt stuff in Greek - desirable properties of ceramics are normally achieved through a high temperature heat treatment
Ceramics Ceramics keramikos - burnt stuff in Greek - desirable properties of ceramics are normally achieved through a high temperature heat treatment process (firing). Usually a compound between metallic
More informationIntroduction to Engineering Materials ENGR2000 Chapter 12: Structures and Properties of Ceramics. Dr. Coates
Introduction to Engineering Materials ENGR2000 Chapter 12: Structures and Properties of Ceramics Dr. Coates 12.1 Introduction Ceramics Compounds between metallic & non-metallic elements Predominantly ionic
More informationCovalent Bonding H 2. Using Lewis-dot models, show how H2O molecules are covalently bonded in the box below.
Covalent Bonding COVALENT BONDS occur when atoms electrons. When atoms combine through the sharing of electrons, are formed. What is a common example of a covalently bonded molecule? When hydrogen atoms
More informationExperiment 2a Models of the Solid State*
Experiment 2a Models of the Solid State* *This lab is adapted from solid-state labs offered at Purdue and Rice Universities. Introduction The structures of metals and simple ionic solids are prototypes
More informationLecture 6 - Bonding in Crystals
Lecture 6 onding in Crystals inding in Crystals (Kittel Ch. 3) inding of atoms to form crystals A crystal is a repeated array of atoms Why do they form? What are characteristic bonding mechanisms? How
More informationCeramics. Ceramic Materials. Ceramics / Introduction. Classifications of Ceramics
Ceramic Materials Outline Structure and Properties of Ceramics Introduction Classifications of Ceramics Crystal Structures Silicate Ceramics Ceramic Phase Diagram Carbon based materials Why study ceramic
More informationDiamond. There are four types of solid: -Hard Structure - Tetrahedral atomic arrangement. What hybrid state do you think the carbon has?
Bonding in Solids Bonding in Solids There are four types of solid: 1. Molecular (formed from molecules) - usually soft with low melting points and poor conductivity. 2. Covalent network - very hard with
More informationMaterials Science and Engineering I
Materials Science and Engineering I Chapter Outline Review of Atomic Structure Electrons, Protons, Neutrons, Quantum number of atoms, Electron states, The Periodic Table Atomic Bonding in Solids Bonding
More informationChapter 3. Crystal Binding
Chapter 3. Crystal Binding Energy of a crystal and crystal binding Cohesive energy of Molecular crystals Ionic crystals Metallic crystals Elasticity What causes matter to exist in three different forms?
More informationReport Form for Experiment 6: Solid State Structures
Report Form for Experiment 6: Solid State Structures Note: Many of these questions will not make sense if you are not reading the accompanying lab handout. Station 1. Simple Cubic Lattice 1. How many unit
More informationThere are four types of solid:
Bonding in Solids There are four types of solid: 1. Molecular (formed from molecules) - usually soft with low melting points and poor conductivity. 2. Covalent network - very hard with very high melting
More informationChapter 6. Chemical Bonding
Chapter 6 Chemical Bonding Section 6.1 Intro to Chemical Bonding 6.1 Objectives Define chemical bond. Explain why most atoms form chemical bonds. Describe ionic and covalent bonding. Explain why most chemical
More informationEarth and Planetary Materials
Earth and Planetary Materials Spring 2013 Lecture 3 2013.01.14 14 1 Close Packed Anion Arrays Closest Packing Coordination number (C.N.) : number of anions bonded to a cation larger cation, higher C.N.
More informationChapter 12 INTERMOLECULAR FORCES. Covalent Radius and van der Waals Radius. Intraand. Intermolecular Forces. ½ the distance of non-bonded
Chapter 2 INTERMOLECULAR FORCES Intraand Intermolecular Forces Covalent Radius and van der Waals Radius ½ the distance of bonded ½ the distance of non-bonded Dipole Dipole Interactions Covalent and van
More informationCovalent Bonding. In nature, only the noble gas elements exist as uncombined atoms. All other elements need to lose or gain electrons
In nature, only the noble gas elements exist as uncombined atoms. They are monatomic - consist of single atoms. All other elements need to lose or gain electrons To form ionic compounds Some elements share
More informationMidterm I Results. Mean: 35.5 (out of 100 pts) Median: 33 Mode: 25 Max: 104 Min: 2 SD: 18. Compare to: 2013 Mean: 59% 2014 Mean: 51%??
Midterm I Results Mean: 35.5 (out of 100 pts) Median: 33 Mode: 25 Max: 104 Min: 2 SD: 18 Compare to: 2013 Mean: 59% 2014 Mean: 51%?? Crystal Thermodynamics and Electronic Structure Chapter 7 Monday, October
More informationCHEMISTRY The Molecular Nature of Matter and Change
CHEMISTRY The Molecular Nature of Matter and Change Third Edition Chapter 12 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 11 INTERMOLECULAR FORCES
More informationAtomic Structure & Interatomic Bonding
Atomic Structure & Interatomic Bonding Chapter Outline Review of Atomic Structure Atomic Bonding Atomic Structure Atoms are the smallest structural units of all solids, liquids & gases. Atom: The smallest
More informationAtomic Structure. Atomic weight = m protons + m neutrons Atomic number (Z) = # of protons Isotope corresponds to # of neutrons
Atomic Structure Neutrons: neutral Protons: positive charge (1.6x10 19 C, 1.67x10 27 kg) Electrons: negative charge (1.6x10 19 C, 9.11x10 31 kg) Atomic weight = m protons + m neutrons Atomic number (Z)
More information3-D Crystal Lattice Images
3-D Crystal Lattice Images All of the following images are crossed-stereo pairs. To view them, cross your eyes and focus. Author's note this material has been expanded and updated, and can be found at
More informationChapter 10: Liquids and Solids
Chapter 10: Liquids and Solids Chapter 10: Liquids and Solids *Liquids and solids show many similarities and are strikingly different from their gaseous state. 10.1 Intermolecular Forces Intermolecular
More informationRutile TiO 2 tetragonal unit cell with a = b = Å, c = Å Fig. 1.32a: Ti positions, 2 per cell, corner(0,0,0) and body center( 21
1 f) Rutile (TiO 2 ), cadmium iodide (CdI 2 ), cadmium chloride (CdCl 2 ) and caesium oxide (Cs 2 O) Together with fluorite, they represent the main AX 2 structure types. Rutile TiO 2 tetragonal unit cell
More informationCHEMICAL BONDING SUTHERLAND HIGH SCHOOL GRADE 10 PHYSICAL SCIENCE TB. 103 K. FALING EDITED: R. BASSON
CHEMICAL BONDING SUTHERLAND HIGH SCHOOL K. FALING EDITED: R. BASSON GRADE 10 PHYSICAL SCIENCE TB. 103 HOW DOES BONDING WORK? The chemical reaction between elements leads to compounds, which have new physical
More informationThe Solid State. Phase diagrams Crystals and symmetry Unit cells and packing Types of solid
The Solid State Phase diagrams Crystals and symmetry Unit cells and packing Types of solid Learning objectives Apply phase diagrams to prediction of phase behaviour Describe distinguishing features of
More informationCHAPTER 2. Atomic Structure And Bonding 2-1
CHAPTER 2 Atomic Structure And Bonding 2-1 Structure of Atoms ATOM Basic Unit of an Element Diameter : 10 10 m. Neutrally Charged Nucleus Diameter : 10 14 m Accounts for almost all mass Positive Charge
More informationChapter 16: Phenomena. Chapter 16 Liquids and Solids. intermolecular forces? Intermolecular Forces. Intermolecular Forces. Intermolecular Forces
Chapter 16: Phenomena Phenomena: The tables below show melting points and boiling points of substances. What patterns do you notice from the data? Melting Boiling Substance Point Point CaO 2886 K 4123
More informationUNIT-1 SOLID STATE. Ans. Gallium (Ga) is a silvery white metal, liquid at room temp. It expands by 3.1% on solidifica-tion.
UNIT-1 SOLID STATE 1 MARK QUESTIONS Q. 1. Name a liquefied metal which expands on solidification. Ans. Gallium (Ga) is a silvery white metal, liquid at room temp. It expands by 3.1% on solidifica-tion.
More informationMaterials for Civil and Construction Engineers CHAPTER 2. Nature of Materials
Materials for Civil and Construction Engineers CHAPTER 2 Nature of Materials Bonds 1. Primary Bond: forms when atoms interchange or share electrons in order to fill the outer (valence) shells like noble
More informationLecture 4! ü Review on atom/ion size! ü Crystal structure (Chap 4 of Nesseʼs book)!
Lecture 4! ü Review on atom/ion size! ü Crystal structure (Chap 4 of Nesseʼs book)! 15 C 4+ 42 Si 4+ Size of atoms! Hefferan and O Brien, 2010; Earth Materials Force balance! Crystal structure (Chap. 4)!
More informationIonic Bonding and Ionic Compounds
Main Ideas Ionic bonds form from attractions between positive and negative ions Differences in attraction strength give ionic and molecular compounds different properties Multiple atoms can bond covalently
More informationChapter 12 Solids and Modern Materials
Sec$on 10.3 An Introduc+on to Structures and Types of Solids Chapter 12 Solids and Modern Materials Sec$on 10.3 An Introduc+on to Structures and Types of Solids Solids Amorphous Solids: Disorder in the
More informationCovalent Bonding. In nature, only the noble gas elements exist as uncombined atoms. All other elements need to lose or gain electrons
In nature, only the noble gas elements exist as uncombined atoms. They are monatomic - consist of single atoms. All other elements need to lose or gain electrons To form ionic compounds Some elements share
More informationCrystal Structure and Chemistry
Crystal Structure and Chemistry Controls on Crystal Structure Metallic bonding closest packing Covalent bonding depends on orbital overlap and geometry Ionic bonding Pauling s Rules Coordination Principle
More informationHigh Temperature Materials. By Docent. N. Menad. Luleå University of Technology ( Sweden )
Course KGP003 Ch. 12 High Temperature Materials By Docent. N. Menad Dept. of Chemical Engineering and Geosciences Div. Of process metallurgy Luleå University of Technology ( Sweden ) Ceramic materials
More informationChapter 6. Preview. Objectives. Molecular Compounds
Section 2 Covalent Bonding and Molecular Compounds Preview Objectives Molecular Compounds Formation of a Covalent Bond Characteristics of the Covalent Bond The Octet Rule Electron-Dot Notation Lewis Structures
More informationChapter 12. Chemical Bonding
Chapter 12 Chemical Bonding Chapter 12 Introduction to Chemical Bonding Chemical Bonding Valence electrons are the electrons in the outer shell (highest energy level) of an atom. A chemical bond is a mutual
More informationStructure of Crystalline Solids
Structure of Crystalline Solids Solids- Effect of IMF s on Phase Kinetic energy overcome by intermolecular forces C 60 molecule llotropes of Carbon Network-Covalent solid Molecular solid Does not flow
More informationChapter 10. Liquids and Solids
Chapter 10 Liquids and Solids Chapter 10 Table of Contents 10.1 Intermolecular Forces 10.2 The Liquid State 10.3 An Introduction to Structures and Types of Solids 10.4 Structure and Bonding in Metals 10.5
More informationHW# 5 CHEM 281 Louisiana Tech University, POGIL(Process Oriented Guided Inquiry Learning) Exercise on Chapter 3. Structures of Ionic Solids. Why?
HW# 5 CHEM 281 Louisiana Tech University, POGIL(Process Oriented Guided Inquiry Learning) Exercise on Chapter 3. Structures of Ionic Solids. Why? Many ionic structures may be described as close-packed
More information3.014 Materials Laboratory Fall LABORATORY 2: Module β 1. Radius Ratios and Symmetry in Ionic Crystals
3.014 Materials Laboratory Fall 2006 LABORATORY 2: Module β 1 Radius Ratios and Symmetry in Ionic Crystals Instructor: Francesco Stellacci Objectives Discover principles of X-ray diffraction from crystalline
More informationCHAPTER 6: CHEMICAL NAMES AND FORMULAS CHAPTER 16: COVALENT BONDING
CHAPTER 6: CHEMICAL NAMES AND FORMULAS CHAPTER 16: COVALENT BONDING 6.1 Introduction to Chemical Bonding A chemical bond is a mutual electrical attraction between the nuclei and valence electrons of different
More informationThe broad topic of physical metallurgy provides a basis that links the structure of materials with their properties, focusing primarily on metals.
Physical Metallurgy The broad topic of physical metallurgy provides a basis that links the structure of materials with their properties, focusing primarily on metals. Crystal Binding In our discussions
More informationAtoms & Their Interactions
Lecture 2 Atoms & Their Interactions Si: the heart of electronic materials Intel, 300mm Si wafer, 200 μm thick and 48-core CPU ( cloud computing on a chip ) Twin Creeks Technologies, San Jose, Si wafer,
More informationChapter 11: Intermolecular Forces. Lecture Outline
Intermolecular Forces, Liquids, and Solids 1 Chapter 11: Intermolecular Forces Lecture Outline 11.1 A Molecular Comparison of Gases, Liquids and Solids Physical properties of substances are understood
More informationSolids. Adapted from a presentation by Dr. Schroeder, Wayne State University
Solids Adapted from a presentation by Dr. Schroeder, Wayne State University Properties of Solids Definite shape, definite volume Particles are CLOSE together, so Attractive forces (bonds or IMF s) are
More informationChemical Bonding Basic Concepts
Chemical Bonding Basic Concepts Valence electrons are the outer shell electrons of an atom. The valence electrons are the electrons that particpate in chemical bonding. Group e - configuration # of valence
More informationChem 241. Lecture 21. UMass Amherst Biochemistry... Teaching Initiative
Chem 241 Lecture 21 UMass Amherst Biochemistry... Teaching Initiative Announcement March 26 Second Exam Recap Calculation of space filling Counting atoms Alloys Ionic Solids Rock Salt CsCl... 2 ZnS Sphalerite/
More informationChapter 7. Ionic & Covalent Bonds
Chapter 7 Ionic & Covalent Bonds Ionic Compounds Covalent Compounds 7.1 EN difference and bond character >1.7 = ionic 0.4 1.7 = polar covalent 1.7 Electrons not shared at
More informationBonding in Solids. What is the chemical bonding? Bond types: Ionic (NaCl vs. TiC?) Covalent Van der Waals Metallic
Bonding in Solids What is the chemical bonding? Bond types: Ionic (NaCl vs. TiC?) Covalent Van der Waals Metallic 1 Ions and Ionic Radii LiCl 2 Ions (a) Ions are essentially spherical. (b) Ions may be
More informationName: Date: Blk: Examine your periodic table to answer these questions and fill-in-the-blanks. Use drawings to support your answers where needed:
Name: Date: Blk: NOTES: BONDING Examine your periodic table to answer these questions and fill-in-the-blanks. Use drawings to support your answers where needed: I. IONIC BONDING Ionic bond: formed by the
More informationCritical Temperature - the temperature above which the liquid state of a substance no longer exists regardless of the pressure.
Critical Temperature - the temperature above which the liquid state of a substance no longer exists regardless of the pressure. Critical Pressure - the vapor pressure at the critical temperature. Properties
More informationForming Chemical Bonds
Forming Chemical Bonds Chemical Bonds Three basic types of bonds 2012 Pearson Education, Inc. Ionic Electrostatic attraction between ions. Covalent Sharing of electrons. Metallic Metal atoms bonded to
More informationBonding. Bringing the atoms together
Bonding Bringing the atoms together More than one atom Until now, we have been consumed with describing individual atoms of elements. However, isolating individual atoms in most elements is an arduous
More informationLecture 2: Atom and Bonding Semester /2013
EMT 110 Engineering Materials Lecture 2: Atom and Bonding Semester 1 2012/2013 Atomic Structure Fundamental Concept Atoms are the structural unit of all engineering materials! Each atoms consist of nucleus
More informationEGN 3365 Review on Bonding & Crystal Structures by Zhe Cheng
EGN 3365 Review on Bonding & Crystal Structures 2017 by Zhe Cheng Expectations on Chapter 1 Chapter 1 Understand materials can be classified in different ways by composition, property, application, or
More informationLecture 05 Structure of Ceramics 2 Ref: Barsoum, Fundamentals of Ceramics, Ch03, McGraw-Hill, 2000.
MME 467 Ceramics for Advanced Applications Lecture 05 Structure of Ceramics 2 Ref: Barsoum, Fundamentals of Ceramics, Ch03, McGraw-Hill, 2000. Prof. A. K. M. Bazlur Rashid Department of MME, BUET, Dhaka
More informationCh. 12 Section 1: Introduction to Chemical Bonding
Name Period Date Chemical Bonding & Intermolecular Forces (Chapter 12, 13 &14) Fill-in the blanks during the PowerPoint presentation in class. Ch. 12 Section 1: Introduction to Chemical Bonding Chemical
More informationChapter 12. Solids and Modern Materials
Lecture Presentation Chapter 12 Solids and Modern Materials Graphene Thinnest, strongest known material; only one atom thick Conducts heat and electricity Transparent and completely impermeable to all
More informationCHEM 121 Introduction to Fundamental Chemistry. Summer Quarter 2008 SCCC. Lecture 7.
CHEM 121 Introduction to Fundamental Chemistry Summer Quarter 2008 SCCC Lecture 7 http://seattlecentral.edu/faculty/lcwest/che121 Forces Between Particles Noble Gas Configurations Ionic Bonding Ionic Compounds
More informationCh 9 Liquids & Solids (IMF) Masterson & Hurley
Ch 9 Liquids & Solids (IMF) Masterson & Hurley Intra- and Intermolecular AP Questions: 2005 Q. 7, 2005 (Form B) Q. 8, 2006 Q. 6, 2007 Q. 2 (d) and (c), Periodic Trends AP Questions: 2001 Q. 8, 2002 Q.
More informationCHAPTER 2: BONDING AND PROPERTIES
CHAPTER 2: BONDING AND PROPERTIES ISSUES TO ADDRESS... What promotes bonding? What types of bonds are there? What properties are inferred from bonding? Chapter 2-1 Atomic Structure (Freshman Chem.) atom
More informationChemical Bond An attraction between the nuclei and valence electrons of different atoms, which binds the atoms together
Chemical Bond An attraction between the nuclei and valence electrons of different atoms, which binds the atoms together When atoms form chemical bonds their valence electrons move around. This makes atoms
More informationCHAPTER 4. Crystal Structure
CHAPTER 4 Crystal Structure We can assume minerals to be made of orderly packing of atoms or rather ions or molecules. Many mineral properties like symmetry, density etc are dependent on how the atoms
More information