Crystal Models. Figure 1.1 Section of a three-dimensional lattice.
|
|
- Isaac Pearson
- 6 years ago
- Views:
Transcription
1 Crystal Models The Solid-State Structure of Metals and Ionic Compounds Objectives Understand the concept of the unit cell in crystalline solids. Construct models of unit cells for several metallic and ionic substances. Calculate various quantities such as atomic radii and theoretical density from unit cell data. Introduction In a piece of crystalline material, either metallic or ionic, the particles show an endless repetition of an orderly arrangement to generate a three-dimensional structure known as a crystal lattice. Part of a simple lattice is shown in Figure 1.1. The unit cell is the most convenient small part of the lattice that, if repeated in three dimensions, generates the entire lattice. An acceptable unit cell for the lattice shown in Figure 0.3(a). Depending on the relative lengths of the sides of the unit cell and the angles that the sides make with each other, a unit cell will belong to one of several crystal systems. In this study we consider unit cells in only the cubic system (where all three sides are equal, designated by the symbol a, and all angles are 90 ) and the hexagonal system (where two sides are equal, designated by a, and one side is longer, designated by c, and the angles are 90, 90, and 120 ); see Figure 0.4b. A primitive unit cell is a unit cell in which only the corners are occupied. In some cases unit cells contain other lattice points in addition to those at the corners; these are called multiple unit cells. A primitive cubic and two multiple cubic unit cells are shown in Experiment Figure 3, along with a multiple hexagonal unit cell. The exploded unit cell diagrams shown in Figure 3 are somewhat misleading because they show that each cell contains mostly empty space. The packing of atoms in a crystal is more realistically shown by the sketches given in Figure 0.2 Figure 0.5for these same unit cells. Figure 1.1 Section of a three-dimensional lattice. a Figure 0.2 Two common crystal systems, (a) is called primitive cubic, and (b) is called hexagonal. Although the spheres shown in Figure 0.3 and Figure 0.4 touch each other, there is considerable empty space in each unit cell. There are three types of open spaces (or holes ) commonly found in unit cells: tetrahedral holes, octahedral holes, and cubic holes (see Figure 1.7), based on the geometric figure describing the atoms around the hole. b
2 Part I: Metals The particles making up the crystal structure of a pure metal consist of identical atoms. Most metals crystallize in the unit cells shown in Figure 0.3 and Figure 0.4. From a careful analysis of these sketches, several properties of the metals can be determined. a Figure 0.3 Two unit cells, (a) the primitive cubic, and (b) the body-centered cubic. b a b c Figure 0.4 Two more unit cells, (a) is the face-centered cubic, also called the cubic close-packed, and (b) the hexagonal closepacked. The hexagonal close-packed unit cell is shown extended in (c) to emphasize the hexagonal shape this lattice has. (a) Primitive Cubic (b) Hexagonal Close-Packed (c) Body-Centered Cubic (d) Face-Centered Cubic or Cubic Close-Packed Figure 0.5 Packing of atoms or anions in a crystal. Each unit cell shows two views of the packing of spheres. The left view shows all of the atoms that sit on the outline of the unit cell. The right view shows the same unit cell with all of the atom parts outside the unit cell taken away. What remains is the actual content of the unit cell. Consider the element polonium, which will crystallize in the primitive cubic unit cell, shown in Figure 0.3a, with a = nm. The length of a side of the unit cell equals twice the radius of an atom (a = 2R); so we can calculate the radius of a Po atom as R a nm nm 0.1 Similar relationships between the unit cell length and the radius of the atom are summarized in Table 0.1 for the other unit cells.
3 The total number of atoms contained within the unit cell is known as the unit cell contents (Z). Again, consider the primitive cubic unit cell for polonium as shown in Figure 0.5a. At first glance you might think there are eight atoms occupying this unit cell, but this is not the case. Although eight atoms are used to outline the unit cell, the actual unit cell is defined in terms of the centers of these atoms; consequently, a given corner atom is really part of eight adjacent unit cells (see Figure 0.5a). Thus only l/8 of a given atom belongs to the unit cell under consideration. Because there are eight such atoms, for the primitive cubic unit cell Z is given as follows: 1/ 8corner Z 8corners 1 atom 0.2 atom All body-centered atoms are completely within the unit cell; any face-centered atom is shared by two unit cells; any edgecentered atom is shared by the number of unit cells around that edge (often 3, 4, or 6), the unit cell content for the various unit cells that we are considering is summarized in Table 1 and Figure 7. a b c Figure 0.6 Diagrams of holes between anions in a crystal. Three kinds of holes are shown in two views. (a) shows a tetrahedral hole, (b) showns an octahedral hole, and (c) shows a cubic hole. The top view shows the anions separated along an axis marked by the dashed line. the lower figure shows the top view of the cluster of anions that surround the hole, looking down that axis. a b c Figure 1.7 The positions of holes in a unit cell. (a)shows the tetrahedral hole, the topmost view is exploded on one axis. You can see the shape of a tetrahedron, with its triangular base and peak. the second picture in the column shows the tetrahedral hole all together. The third picture shows the hole exploded on all axes, and the fourth picture shows the hole re-assembled in the same orientation as in picture three. (b) Shows the same set of views of an octahedral hole and (c) shows the same set of views of a cubic hole. The crystal coordination number (CN) of an atom is the number of nearest neighbor atoms in the crystal structure, Figure 8 shows that CN = 6 for a given corner atom in the primitive cubic unit cell. (This is the value for any atom in the unit cell.) Table 0.1 also summarizes the values of CN for the cubic unit cells to be studied in this experiment.
4 Unit cell Length Radius Relationship Z V CN Primitive cubic a = 2R 1 a 3 6 Body-centered cubic a 3 = 4R 2 a 3 8 Face-centered cubic a 2 = 4R 4 a 3 12 Hexagonal closest packed a = 2R 2 a 2 c sin 60 o 12 Diamond a 3 = 8R??? Z = number of atoms per unit cell V = unit cell volume CN = coordination number a = unit cell length R = radius of atom or anion? = Figure it out yourself! Table 0.1 Summary of properties of various unit cells. If the unit cell dimensions and cell content are known for a substance, the volume of the unit cell and the mass of the atoms in the unit cell can be calculated. For the cell of polonium, the volume is: and the mass is: V a 3 ( cm) cm m Z M N A 1 atom 209 g/mol atoms/mole g 0.4 Knowing the mass and volume of the unit cell allows the calculation of the theoretical (or crystallographic) density (d) of the substance d m v g cm g/cm Part II: Ionic Crystals The crystal structures of ionic compounds may be pictured as arrays of closely stacked larger ions, creating holes into which the smaller counter-ions can fit. Because anions are usually larger than cations, we consider the anions to define the original unit cell and the cations to occupy the holes. For example, in the sodium chloride unit cell shown in Figure 0.8, the Na + cations can be considered to occupy the octahedral holes in a slightly expanded Cl -anion face-centered cubic unit cell. The unit cells of ionic compounds can be analyzed to obtain various properties just as were the unit cells of metals. For example, the cell content for each type of ion in the sodium chloride unit cell is Z 12 edges Z 8 corners 1/4 cation 1 cation 4 cations edge 1/8 anion 1/2 anions 6 sides 4 anions corner side 0.6
5 The ratio of Z + /Z is the same as the ratio of ions in the empirical formula. Each ion has a crystal coordination number, but this now refers to the number of oppositely charged ions that are nearest neighbors. For example, in NaCl, CN + = 6 and CN = 6. The ratio of CN + /CN - is the inverse of the ratio of Z + /Z. When calculating the theoretical density, it is helpful to begin by finding the separate masses of the cations and anions in the unit cell. For example, for NaCl having a unit cell length of a = nm, the masses of the cations and anions in the cell as well as the cell volume are calculated according to m Z Atomic Mass of cation cations/mol 4 cations g/mol g 0.7 cations/mol m Z Atomic mass of anion anions/mol 4 anions g/mol anions/mol g 0.8 m m g g g 1.9 V nm10 7 cm/1 nm cm d m V g cm g/cm Crystal structures of ionic substances are influenced both by the relative sizes of the anions and cations, and by the ionic charges. Depending on the relative sizes of the ions, a cation may fit into a tetrahedral hole (the smallest) or might fit into a cubic hole (the largest). a Figure 0.8 The Sodium chloride unit cell b Radius ratio (r + /r - ) Coordination number (CN+) Hole geometry Holes per anion tetrahedral octahedral 1 > cubic 1 Table 0.2 The radius ratio rule Table 0.2 indicates the values of the radius ratio (r + /r - ) needed by a cation so that it will fit into a certain type of hole. Using r + = nm for the Na + cation and nm for the Cl anion in NaCl gives r + /r - = nm/0.181 nm =
6 This radius ratio value corresponds to the octahedral hole geometry entry in the table. Because there is one octahedral hole per Cl anion, all these holes must be occupied by Na + cations in order to achieve the one-to-one ratio of cation to anion required by the formula NaCl. The empirical relationships expressed in Table 0.2 are actually violated by many crystalline species and should be used only as general guidelines. Experimental Procedure Your instructor will familiarize you with the kit of spheres and connectors you will be using to build the models of the unit cells. The kit will contain four different sizes of spheres. For each structure, construct the model and analyze it to determine the unit cell parameters requested on the table at the end of this experiment. Caution! Please stuff wet paper towels into the drains of the sinks at your lab station. Otherwise, you may lose a few beads into the drains. Part I: Metals (Use spheres of uniform size for each structure in this part.) A. -Ni Structure C. -Fe Structure Prepare the three layers shown in the Figure. Place layer 2 on layer 1; then place layer 3 on layer 2. Keep the relative orientations the same as given in the figure and a cubic structure will result. B. -Ni Structure Prepare the three layers shown. Place layer 2 on layer 1 so that this single sphere nestles down in the hole between the four atoms in layer 1. Place layer 3 on layer 2. Keep the relative orientations of layer 1 and 3 the same as given in the figure to generate a cubic structure. D. Silicon Structure Prepare the three layers shown. Place layer 2 on layer 1 so that this single sphere nestles down in the hole between the three left-most atoms of layer 1. Place layer 3 on layer 2. Keep the relative orientations of layers 1 and 3 the same as given in the figure, and a hexagonal closest-packed structure will result. It may be necessary to support the right-hand portion of the top layer to keep it from falling. Part II: Ionic Crystals A. CsCl Structure Prepare the five layers shown. Assemble the layers, keeping the relative orientations of the layers the same as given. It may be necessary to support two of the corners of the model. This structure is called a diamondlike structure. B. AgCl Structure Prepare the three layers shown above, using the large and medium spheres. The large spheres in the first and third layers should not quite touch each other in order to make room for the medium sphere of the second layer. Assemble the layers, keeping the relative orientations of the layers the same as given in the figure. A cubic structure will result. Prepare the three layers shown, using the large and small spheres, Assemble the layers, keeping the relative orientations of the layers the same as given in the figure. A cubic structure will result.
7 C. CuI Structure D. Li 2 S Structure Prepare the five layers shown, using the large and small spheres. Assemble the layers, keeping the relative orientations of the layers the same as given in the figure and, again, slightly expand the structures in layers 1, 3, and 5. The small spheres should nestle down in the holes created by the large spheres. A cubic structure will result. Prepare the five layers shown, using the large and small spheres. Assemble the layers, keeping the relative orientations of the layers the same as given in the figure. A cubic structure will result. Enrichment links: Calculations Part I: Metals In each case, use your model to identify the type of unit cell. A. -Ni Structure Using a = nm, calculate the atomic radius from the appropriate unit cell length-radius relation given in Table 1. Using the unit cell content (Z), calculate the mass of the atoms in the unit cell. Use the value of a to calculate the volume of the unit cell. Now find the theoretical density of metallic nickel in this crystal form. B. -Ni Structure Identify the unit cell (a = nm, c = nm), and calculate the atomic radius and the theoretical density of metallic nickel in this second crystal form. C. -Fe Structure Identify the unit cell (a = nm), and calculate the atomic radius and the theoretical density of metallic iron in this crystal form. D. Silicon Structure Identify the unit cell (a = nm), and calculate the atomic radius and theoretical density of silicon. Part II: Ionic Compounds A. CsCl Structure Using r + = nm and r = 0.18 nm, calculate r + /r -. From Table 2, ascertain the hole geometry and the cation coordination number (CN + ). Determine if all these holes are occupied by the cations in order to achieve the cation-toanion ratio expressed by the empirical formula of the compound. Identify each ion in your model as being corner, body-centered, face-centered, or edge-centered. Calculate Z + and Z, using the fractional contribution. Use Z + and Z to calculate the masses of all ions (m +, m, m) in the unit cell as described previously. Find the volume of the cubic unit cell given that a = nm. Calculate the theoretical density of CsCl. Finally, describe the type of cubic unit cell defined by the Cl anions, and use Table 0.1 to determine the coordination number (CN ) of these anions. Note: The entry for Z in Table 0.1 should be the same as your calculated value for Z. B. AgCl Structure Using r + = nm, r = nm, and a = nm, repeat the calculations for AgCl. C. CuI Structure Using r + = nm, r = nm, and a = nm, repeat the calculations for CuI. D. Li 2 S Structure Using r + = nm, r = nm, and a = nm, repeat the calculations for Li 2 S.
8 Arrangement of Structure Atoms Part I: Metals Radius (cm) CN Z Mass (g) Volume (cm) Density (g/cm 3 ) Ni -Ni -Fe Si Structure Arrangement of Hole Geometry Anions Part II: Ionic Crystals Fraction of Holes Filled CN + CN - Z + Z - CsCl AgCl CuI Li 2 S Structure m + (g) m - (g) Mass (g) Volume (cm 3 ) Density (g/cm 3 ) CsCl AgCl CuI Li 2 S
Experiment 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 informationCRYSTAL STRUCTURES WITH CUBIC UNIT CELLS
CRYSTAL STRUCTURES WITH CUBIC UNIT CELLS Crystalline solids are a three dimensional collection of individual atoms, ions, or whole molecules organized in repeating patterns. These atoms, ions, or molecules
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 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 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 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 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 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 informationStates of Matter SM VIII (post) Crystallography. Experimental Basis. Experimental Basis Crystal Systems Closed Packing Ionic Structures
States of Matter SM VIII (post) Crystallography Experimental Basis Crystal Systems Closed Packing Ionic Structures Ref 12: 8 22-1 Experimental Basis is X-ray diffraction; see HT Fig. 21.1, Pet. Fig. 12.43
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 informationFor this activity, all of the file labels will begin with a Roman numeral IV.
I V. S O L I D S Name Section For this activity, all of the file labels will begin with a Roman numeral IV. A. In Jmol, open the SCS file in IV.A.1. Click the Bounding Box and Axes function keys. Use the
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 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 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 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 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 informationAdvanced Ceramics for Strategic Applications Prof. H. S. Maiti Department of Mechanical Engineering Indian Institute of Technology, Kharagpur
Advanced Ceramics for Strategic Applications Prof. H. S. Maiti Department of Mechanical Engineering Indian Institute of Technology, Kharagpur Lecture -3 Crystal Structure Having made some introductory
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 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 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 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 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 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 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 informationSolid State. Subtopics
01 Solid State Chapter 01: Solid State Subtopics 1.0 Introduction 1.1 Classification of solids 1.2 Classification of crystalline solids 1.3 Unit cell, two and three dimensional lattices and number of atoms
More informationName TA Name Lab Sec # ALL work must be shown to receive full credit. Due Due in lecture at 1:30 p.m. Wednesday, January 28th
Chem 1515 Section 2 Problem Set #2 Spring 1998 Name TA Name Lab Sec # ALL work must be shown to receive full credit. Due Due in lecture at 1:30 p.m. Wednesday, January 28th PS2.1. Indicate the type of
More informationInorganic Exam 1 Chm October 2010
Inorganic Exam 1 Chm 451 28 October 2010 Name: Instructions. Always show your work where required for full credit. 1. In the molecule CO 2, the first step in the construction of the MO diagram was to consider
More information4. Interpenetrating simple cubic
2 1. The correct structure t of CsClCl crystal is 1. Simple cubic 2. Body centered cubic 3. Face centered cubic 4. Interpenetrating simple cubic If corner as well as the particle at the center are same
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 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 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 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 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 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 informationProperties of Liquids and Solids. Vaporization of Liquids. Vaporization of Liquids. Aims:
Properties of Liquids and Solids Petrucci, Harwood and Herring: Chapter 13 Aims: To use the ideas of intermolecular forces to: Explain the properties of liquids using intermolecular forces Understand the
More informationProperties of Liquids and Solids. Vaporization of Liquids
Properties of Liquids and Solids Petrucci, Harwood and Herring: Chapter 13 Aims: To use the ideas of intermolecular forces to: Explain the properties of liquids using intermolecular forces Understand the
More information9 Crystal Structures
9 Crystal Structures Supporting interactive 3D images of crystal structures and more advanced material may be found at:http://www-teach.ch.cam.ac.uk/links/3dindex.html www.xtremepapers.com A Introduction
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 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 informationVERY SHORT ANSWER TYPE QUESTIONS (1 Mark)
UNIT I 10 Chemistry-XII THE SOLID STATE VERY SHORT ANSWER TYPE QUESTIONS (1 Mark) Q. 1. What do you mean by paramagnetic substance? Ans. Weakly attracted by magnetic eld and these substances are made of
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 information1 8 =1 8 8 =1 6 =3. Unit cell Atoms at corner Atoms at faces Atoms at centre. Total no. of atoms per unit cell. bcc. fcc
Q. No. Amorphous substances show () Short and long range order (2) Short range order (3) Long range order (4) Have no sharp M.P. Option and 3 are correct Option 2 2 and 3 are correct Option 3 3 and 4 are
More informationChm October Molecular Orbitals. Instructions. Always show your work for full credit.
Inorganic Exam 2 Chm 451 29 October 2009 Name: Instructions. Always show your work for full credit. Molecular Orbitals 1. (4 pts) An unusual structure, and one for which there are probably no real examples
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 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 informationIONIC AND METALLIC BONDING
Name IONIC AND METALLIC BONDING Chem 512 Homework rint this sheet, answer the questions and turn it in as a HARD COY A. Matching Match each description in Column B with the correct term in Column A. Write
More informationCondensed Matter A Week 2: Crystal structure (II)
QUEEN MARY, UNIVERSITY OF LONDON SCHOOL OF PHYSICS AND ASTRONOMY Condensed Matter A Week : Crystal structure (II) References for crystal structure: Dove chapters 3; Sidebottom chapter. Last week we learnt
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 informationTo gain a working knowledge of unit cells, packing efficiency, coordination numbers and their relationship to each other.
Solid State Modeling PURPOSE A B To explore some simple solid state structures. To explore unit cell stoichiometry. GOALS To visualize the three-dimensional arrangement of atoms and ions in common solid
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 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 informationThe Periodic Table and Chemical Reactivity
The and Chemical Reactivity Noble gases Less electronegative elements More electronegative elements Then what is electronegativity? The tendency of an atom to attract an electron (or electron density)
More informationSOLID STATE MODULE - 3. Objectives. Solid State. States of matter. Notes
Solid State MODULE - 3 8 SOLID STATE Y ou are aware that the matter exists in three different states viz., solid, liquid and gas. In these, the constituent particles (atoms, molecules or ions) are held
More informationChemWiki BioWiki GeoWiki StatWiki PhysWiki MathWiki SolarWiki
Ashley Robison My Preferences Site Tools Popular pages MindTouch User Guide FAQ Sign Out If you like us, please share us on social media. The latest UCD Hyperlibrary newsletter is now complete, check it
More informationValence electrons are the electrons in the highest occupied energy level of an element s atoms.
7.1 Periodic Trends > Valence Electrons Valence electrons are the electrons in the highest occupied energy level of an element s atoms. 1 of 31 Periodic Trends > 2 of 31 Periodic Trends > 3 of 31 7.1 Periodic
More informationIonic bonding. Characteristics of ionic compounds. The ionic to covalent continuum. Not believed at first, but got the 1903 Nobel prize
Ionic bonding umany compounds can be thought of as a collection of ions (M n+, X n- ) held together electrostatically uthis idea arose out of experiments by Arrhenius looking at the conductivity of solutions
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 informationPractice Problems Set II
P1. For the HCP crystal structure, (a) show that the ideal c/a ratio is 1.633; (b) show that the atomic packing factor for HCP is 0.74. (a) A sketch of one-third of an HCP unit cell is shown below. Consider
More informationGeol /19/06 Labs 5 & 6 Crystal Chemistry Ionic Coordination and Mineral Structures
Geol 2311 9/19/0 Labs 5 & Crystal Chemistry Ionic Coordination and Mineral Structures Handout Oral Mineral Tray Report Samples Ionic Coordination Exercise Investigating Mineral Structures using XtalDraw
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 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 informationClass XII Chapter 1 The Solid State Chemistry. Define the term amorphous give a few examples of amorphous solids.
Book Name: NCERT Solution Question 1: Define the term amorphous give a few examples of amorphous solids. Solution 1: Amorphous solids are the solids whose constituent particles are of irregular shapes
More informationUnit wise Marks Distribution of 10+2 Syllabus
Unit wise Marks Distribution of 10+2 Syllabus S.No Unit Name Marks 1 I Solid State 4 2 II Solutions 5 3 III Electro Chemistry 5 4 IV Chemical Kinetics 5 5 V Surface Chemistry 4 6 VI General Principles
More informationExperiment 3: Modeling the Solid State CH3500: Inorganic Chemistry, Plymouth State University
Experiment 3: Modeling the Solid State CH3500: Inorganic Chemistry, Plymouth State University Adapted from Experiment 2. Solid State Structure and Properties, Teaching General Chemistry: A Materials Science
More informationBig Idea: Ionic Bonds: Ionic Bonds: Metals: Nonmetals: Covalent Bonds: Ionic Solids: What ions do atoms form? Electron Electron
Chapter 13: Phenomena Phenomena: Scientists measured the bond angles of some common molecules. In the pictures below each line represents a bond that contains 2 electrons. If multiple lines are drawn together
More informationClass XII Chapter 1 The Solid State Chemistry
Question 1.1: Define the term 'amorphous'. Give a few examples of amorphous solids. Amorphous solids are the solids whose constituent particles are of irregular shapes and have short range order. These
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 informationRam Seshadri MRL 2031, x6129, These notes complement chapter 6 of Anderson, Leaver, Leevers and Rawlings
Crystals, packings etc. Ram Seshadri MRL 2031, x6129, seshadri@mrl.ucsb.edu These notes complement chapter 6 of Anderson, Leaver, Leevers and Rawlings The unit cell and its propagation Materials usually
More informationANALYSIS OF HYDRATES
1 ANALYSIS OF HYDRATES INTRODUCTION An ionic compound is made of positive and negative ions, called cations and anions, respectively. At room temperature, all ionic compounds are solid. Within a solid
More informationDESCRIPTIVE INORGANIC CHEMISTRY March 24, 2011 INSTRUCTIONS: PRINT YOUR NAME > NAME.
DESCRIPTIVE INORGANIC CHEMISTRY QUIZ II March 24, 2011 INSTRUCTIONS: PRINT YOUR NAME > NAME. SHOW YOUR WORK FOR PARTIAL CREDIT THE LAST PAGE IS A Periodic Table Work 5 of these (40 pts) R = 0.08206 lit-atm/mol-k
More informationChapter 13: Phenomena
Chapter 13: Phenomena Phenomena: Scientists measured the bond angles of some common molecules. In the pictures below each line represents a bond that contains 2 electrons. If multiple lines are drawn together
More informationActivity 5&6: Metals and Hexagonal Close-Packing
Chemistry 150 Name(s): Activity 5&6: Metals and Hexagonal Close-Packing Metals are chemicals characterized by high thermal and electrical conductivity, malleability and ductility. Atoms are the smallest
More informationIonic and Metallic Bonding
Ionic and Metallic Bonding 7.1 Ions BONDING AND INTERACTIONS Essential Understanding electrically charged. Ions form when atoms gain or lose valence electrons, becoming Lesson Summary Valence Electrons
More informationcharacter table, determine the reducible representation and irreducible components for the σ-bonding SALCs.
Chm 451 with Dr. Mattson Exam 2 Name: 27 October 2011 Earlier this month Dan Shechtman won the Nobel Prize in chemistry for his discovery of quasicrystals such as the one shown at right consisting of silver,
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 informationCHEM Principles of Chemistry II Chapter 10 - Liquids and Solids
CHEM 1212 - Principles of Chemistry II Chapter 10 - Liquids and Solids 10.1 Intermolecular Forces recall intramolecular (within the molecule) bonding whereby atoms can form stable units called molecules
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 informationField Trips. Field Trips
Field Trips Saturday field trips have been scheduled October 9, October 23 and December 4 Last all day (9:00 AM to 4:00 PM) Bus transportation provided from campus Joint with GG101 laboratory, GG101 Section
More informationChemical Bonding Ionic Bonding. Unit 1 Chapter 2
Chemical Bonding Ionic Bonding Unit 1 Chapter 2 Valence Electrons The electrons responsible for the chemical properties of atoms are those in the outer energy level. Valence electrons - The s and p electrons
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 informationIONIC AND METALLIC BONDING
7 IONIC AND METALLIC BONDING Chapter Test B A. Matching Match each term in Column B with the correct description in Column A. Write the letter of the correct term on the line. Column A Column B 1. compound
More informationCHEM1902/ N-2 November 2014
CHEM1902/4 2014-N-2 November 2014 The cubic form of boron nitride (borazon) is the second-hardest material after diamond and it crystallizes with the structure shown below. The large spheres represent
More informationPhysical Chemistry I. Crystal Structure
Physical Chemistry I Crystal Structure Crystal Structure Introduction Crystal Lattice Bravis Lattices Crytal Planes, Miller indices Distances between planes Diffraction patters Bragg s law X-ray radiation
More information4/4/2013. Covalent Bonds a bond that results in the sharing of electron pairs between two atoms.
A chemical bond is a mutual electrical attraction between the nucleus and valence electrons of different atoms that binds the atoms together. Why bond? As independent particles, atoms have a high potential
More informationChapter 13: Phenomena
Chapter 13: Phenomena Phenomena: Scientists measured the bond angles of some common molecules. In the pictures below each line represents a bond that contains 2 electrons. If multiple lines are drawn together
More informationCHEMISTRY. The correlation between structure and properties helps in discovering new solid materials with desired properties
CHEMISTRY 1 The correlation between structure and properties helps in discovering new solid materials with desired properties like high temperature superconductors, magnetic materials, biodegradable polymers
More informationCHAPTER 3 THE STRUCTURE OF CRYSTALLINE SOLIDS PROBLEM SOLUTIONS
CHAPTER THE STRUCTURE OF CRYSTALLINE SOLIDS PROBLEM SOLUTIONS Fundamental Concepts.1 What is the difference between atomic structure and crystal structure? Atomic structure relates to the number of protons
More informationWhat happens when substances freeze into solids? Less thermal energy available Less motion of the molecules More ordered spatial properties
Chapter #16 Liquids and Solids 16.1) Intermolecular Forces 16.2) The Liquid State 16.3) An Introduction to Structures and Types of Solids 16.4) Structure and Bonding of Metals 16.5) Carbon and Silicon:
More informationCrystallographic structure Physical vs Chemical bonding in solids
Crystallographic structure Physical vs Chemical bonding in solids Inert gas and molecular crystals: Van der Waals forces (physics) Water and organic chemistry H bonds (physics) Quartz crystal SiO 2 : covalent
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: 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 Coordination and Silicate Structures
Ionic Coordination and Silicate Structures Pauling s Rules A coordination polyhedron of anions forms around a cation Ionic distance determined by radii Coordination number determined by radius ratio. May
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 informationChapter 10. Liquids and Solids
Chapter 10 Liquids and Solids Section 10.1 Intermolecular Forces Section 10.1 Intermolecular Forces Section 10.1 Intermolecular Forces Section 10.1 Intermolecular Forces Metallic bonds Covalent bonds Ionic
More informationChapter 2: INTERMOLECULAR BONDING (4rd session)
Chapter 2: INTERMOLECULAR BONDING (4rd session) ISSUES TO ADDRESS... Secondary bonding The structure of crystalline solids 1 REVIEW OF PREVIOUS SESSION Bonding forces & energies Interatomic vs. intermolecular
More informationDifferentiaton: Redistribution of mass (elements) and energy by chemical & physical processes. Goal: Quantitative understanding of those processes.
Differentiaton: Redistribution of mass (elements) and energy by chemical & physical processes. Goal: Quantitative understanding of those processes. 1 2 What controls the periodicity of behavior of the
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 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 informationME 254 MATERIALS ENGINEERING 1 st Semester 1430/ st Med-Term Exam (1.5 hrs)
ME 254 MATERIALS ENGINEERING 1 st Semester 1430/1431 1 st Med-Term Exam (1.5 hrs) قسم الهندسة الميكانيكية Question 1 a) Classify the materials based on their properties and performance, give some examples.
More informationChapter 7 Ionic and Metallic Bonding
Chapter 7 Ionic and Metallic Bonding Section 7.1 - Ions OBJECTIVES: Determine the number of valence electrons in an atom of a representative element. Section 7.1 - Ions OBJECTIVES: Explain how the octet
More information