Chemistry
Ionic Solids
Ionic solids are a type of crystalline solid composed of positively and negatively charged ions held together by electrostatic forces. They have high melting and boiling points due to the strong ionic bonds. Ionic solids are typically brittle and non-conductive in their solid state, but conduct electricity when melted or dissolved in water due to the mobility of the ions.
Written by Perlego with AI-assistance
Related key terms
1 of 5
7 Key excerpts on "Ionic Solids"
eBook - PDF- Young, William Vining, Roberta Day, Beatrice Botch(Authors)
- 2017(Publication Date)
- Cengage Learning EMEA(Publisher)
AlbertSmirnov/iStockphoto.com 13 The Solid State Unit Outline 13.1 Introduction to Solids 13.2 Metallic Solids 13.3 Ionic Solids 13.4 Bonding in Metallic and Ionic Solids 13.5 Phase Diagrams In This Unit… In Intermolecular Forces and the Liquid State (Unit 12), we focused on intermolecular forces, the non bonding interactions between collections of atoms and molecules, and how these forces manifest themselves in the physical properties of liquids. In this unit we continue this explora-tion with the study of structure and bonding in solids. We begin by look-ing at the structural features of some simple types of solids. Then we investigate bonding in different types of solids, and conclude by tying the three states of matter together in what is known as a phase diagram. © Vladmir Fedorchuk/Fotolia.com Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-300 Unit 13 The Solid State 372 13.1 Introduction to Solids 13.1a Types of Solids Most solids are best described as either crystalline or amorphous. A crystalline solid is one in which the particles in the solid are arranged in a regular way. There is long-range order extending over the entire crystal, which can be described as repeating atomic- or molecular-level building blocks. The atomic-level order in a crystalline solid is often reflected in the well-defined faces of the crystal. Examples of pure substances that are crys-talline solids at room temperature and pressure are diamond, table salt (NaCl) , and sugar (C 12 H 22 O 11 ) . In an amorphous solid , the particles that make up the solid are arranged in an irregular manner and the solid lacks long-range order. Many important solid materials, such as synthetic fibers, plastics, and glasses, are amorphous, but pure solid substances, such as elemental phosphorus or sulfur, may also exist in amorphous forms.
eBook - PDFIntroduction to Solid State Ionics
Phenomenology and Applications
- C. S. Sunandana(Author)
- 2015(Publication Date)
- CRC Press(Publisher)
1 1 What Is Solid State Ionics? 1.1 Perspectives What is solid state ionics? To answer this question, we should know what an ion is. Hydrogen and oxygen ions rule this world, with a little help from carbon. The people of this terra firma stand firmly on essentially ionic structures made of Si 4+ and O = aided a little by Ca ++ and Mg ++ . H + is a proton and O = is stable ion. An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving the atom a net positive or negative electrical charge and, more importantly, mobility and stability. Ions can be created by both chemical and physical means. In chemical terms, if a neutral atom loses one or more electrons, it has a net positive charge and is known as a cation. If an atom gains electrons, it has a net negative charge and is known as an anion. An ion consisting of a single atom is an atomic or monatomic ion; if it consists of two or more atoms, it is a molecular or polyatomic ion. In the case of physical ionization of a medium, such as a gas, what are known as “ion pairs” are created by ion impact, and each pair consists of a free electron and a positive ion. The word ion comes from the Greek ἰ όν ( ion ), meaning “going,” the present participle of ἰ έναι ( ienai ), meaning “to go.” This term was introduced by English physicist and chemist Michael Faraday in 1834 for the then-unknown species that goes from one electrode to the other through an aqueous medium. Faraday knew that since metals dissolved into and entered a solution at one electrode, and new metal came forth from the solution at the other electrode, some kind of substance moved through the solution in a current , conveying matter from one place to the other . Faraday also introduced the words anion for a negatively charged ion and cation for a positively charged one.
eBook - PDF- Paul Flowers, Klaus Theopold, Richard Langley, William R. Robinson(Authors)
- 2019(Publication Date)
- Openstax(Publisher)
10.5 The Solid State of Matter Some substances form crystalline solids consisting of particles in a very organized structure; others form amorphous (noncrystalline) solids with an internal structure that is not ordered. The main types of crystalline solids are Ionic Solids, metallic solids, covalent network solids, and molecular solids. The properties of the different kinds of crystalline solids are due to the types of particles of which they consist, the arrangements of the particles, and the strengths of the attractions between them. Because their particles experience identical attractions, crystalline solids have distinct melting temperatures; the particles in amorphous solids experience a range of interactions, so they soften gradually and melt over a range of temperatures. Some crystalline solids have defects in the definite repeating pattern of their particles. These defects (which include vacancies, atoms or ions not in the regular positions, and impurities) change physical properties such as electrical conductivity, which is exploited in the silicon crystals used to manufacture computer chips. 10.6 Lattice Structures in Crystalline Solids The structures of crystalline metals and simple ionic compounds can be described in terms of packing of spheres. Metal atoms can pack in hexagonal closest- packed structures, cubic closest-packed structures, body-centered structures, and simple cubic structures. The anions in simple ionic structures commonly adopt one of these structures, and the cations occupy the spaces remaining between the anions. Small cations usually occupy tetrahedral holes in a closest-packed array of anions. Larger cations usually occupy octahedral holes. Still larger cations can occupy cubic holes in a simple cubic array of anions. The structure of a solid can be described by indicating the size and shape of a unit cell and the contents of the cell.
eBook - ePub- Jeffrey Gaffney, Nancy Marley(Authors)
- 2017(Publication Date)
- Elsevier(Publisher)
Chapter 11Solids
Abstract
This chapter reviews the types of solids including their chemical structure and properties. The seven types of crystal lattice structures and the four substructures are explained. Types of crystalline solids covered are Ionic Solids, molecular solids, atomic solids, and metallic solids. Discussions of Ionic Solids include the determination of lattice energy and its relation to melting points and other properties. Properties of molecular solids are linked to the strength of the intermolecular forces between the constituent species. Examples of atomic solids: the allotropes of carbon and silicon are discussed with respect to the differences in structure and bonding. Metallic bonding is introduced to explain the unique properties of metallic solids and band theory is covered to explain the behavior of semiconductors. The properties and structures of amorphous solids are covered including microcrystalline solids, ceramics, glasses, and organic polymers. A detailed discussion of organic polymers is left to Chapter 13 .Keywords
Crystal lattice; Unit cell; Coordination number; Molecular solids; Atomic solids; Semiconductor; P-type; N-type; P-n junction; Band theoryOutline11.1Crystalline Solids11.2Ionic Solids11.3Molecular Solids11.4Atomic Solids11.5Metallic Solids11.6Amorphous SolidsImportant TermsStudy QuestionsProblemsIn previous chapters, the focus has been on the structure and behavior of individual molecules or small groups of molecules. The properties of the macromolecular solids are dependent on this structure and behavior of the individual molecules that make up the solids. Chapter 1
- M Z A Munshi(Author)
- 1995(Publication Date)
- World Scientific(Publisher)
2 Microscopically, the ionic conductivity in solids is caused by the existence of defects or disorders. A perfect crystal of an ionic compound would be an insulator. 3 Based on the types of defects or disorders, the superIonic Solids can be classified as follows: Point defect (zero dimensional) type: Here, the concentration of the point defects is 1 2 B. V. Ratnakumar and S. R. Narayanan 10 20 cm-3 . Molten - sub-lattice type: a case of liquid-like molten sub-lattice, in which the number of ions of a particular type is less than the number of sites available for them. The number of mobile ionic charge carriers is 10 cm . These are often marked by a channeled or layered structure. Despite the fact that cations as well as anions can move in the solid lattice, mobility of cations is generally favored due to their small ionic size. Many of the known superIonic Solids are cationic conductors and especially of small size, e.g. Li + , Na + , K + . Also many of the solid electrolytes involve a monovalent ion, owing to relatively strong coulombic interactions between divalent or trivalent ions within the lattice. This is an oversimplification of the underlying mechanism A more rigorous correlation between the ionic conduction and the structural aspects of the solid electrolytes has been attempted recently. 4 7 H. DEFECTS AND DISORDERS 2.1 Types of Defects The lattice defects present in an ionic solid are conventionally represented using Kroger-Vink notation, which specifies the nature, location and effective charge of a defect relative to the neutral unperturbed lattice. The various kinds of point imperfections possible (Figure 1) in an ionic crystal (MX, M and X are monovalent) taking into account the requirement of charge neutrality are as follows. (i) Vacancies: a missing M ion in a pure binary compound missing from its normal site depicted as V M .
eBook - PDFElectrical Conduction in Solid Materials
Physicochemical Bases and Possible Applications
- J. P. Suchet, B. R. Pamplin(Authors)
- 2013(Publication Date)
- Pergamon(Publisher)
Pari I Physicochemical Bases This page intentionally left blank Chapter 1 Conductors 1.1. Interatomic bonds A solid phase contains a very large number of atoms, all identical in the case of an element, or of several different kinds in the case of an alloy or chemical compound. These atoms are linked with one another by means of their electrons on which cohesion of the solid depends. But these bonds can be of several different types, depending a great deal on the total ionization energies of the atoms present, in other words the energies needed to move all the valency electrons of these atoms to infinity. For an atom of a given element, the term of this operation is a positively charged ion, the electronic formula of which is that of the rare gas preceding the element in the Periodic Table of Elements. Table 1.1 gives these energies in electron volts for the main elements. Atoms for elements which have low numbers (less than about 35) on this table combine with one another in the form of compact stacks of spheres, and part of their valency electrons escapes from the attraction of their nuclei, forming a gas of delocalized electrons ready to move in an electric field. This is the metallic bond, to be found in metals and alloys, where it gives rise to chemical formulae, the lower indices of which are usually neither simple nor unique for a given association of elements. Electrical conduction of phases with this type of bond is naturally high, and entirely due to the delocalized electron gas. When one solid phase contains atoms of elements for which the numbers in Table 1.1 are in some cases lower and in other cases higher than 35, atoms in elements with numbers above 35 do not lose their electrons but tend to complete their electronic valency octet at the ex-pense of atoms of elements with numbers below 35, thus attaining the 3
eBook - PDFMaterials Principles and Practice
Electronic Materials Manufacturing with Materials Structural Materials
- Charles Newey, Graham Weaver(Authors)
- 2013(Publication Date)
- Butterworth-Heinemann(Publisher)
Because defects in the structure of a material play an important role in fracture, the tensile strength predicted by the atomic separation model is an order of magnitude higher than the measured tensile strength. There is a very strong (quantum mechanical) repulsion between atoms which get close enough for their cores to interact. The energy trade-off between repulsion of the atomic cores and the attraction due to the outer electrons determines the amount of 'sticking'. 112 3.4 Ionic bonds and ionic crystals Ionically bonded crystals are within a wider group of engineering materials classed as ceramics, being generally hard, brittle and insulating. Sodium chloride (common salt) is often the first ionic compound to which people are introduced, although it is not well known for its engineering properties and after a brief scientific comparison we will deal with it no further. We will however examine various oxides which form structures with significant engineering implications arising from their refractory or electrical nature. Many compounds are not purely ionic. For example silicates contain both ionic and covalent bonds. But here we will discuss materials which have a predominant ionic component. Let's begin by looking at the nature of the bond. 3.4.1 The ionic bond mechanism In Ionic Solids the atoms are bound together as charged ions. The electrostatic forces involved are not directional so a feature of all ionic crystals is that the nearest neighbours of any ion are several ions of opposite sign. The resulting electrostatic attraction balances the repulsive forces. What are the repulsive effects? There are two: (a) The inevitable core repulsion. This dictates how close the nearest neighbours can get. (b) Ions of like sign repel. Electrostatic forces vary as 1/r 2 — the attraction of (oppositely charged) nearest neighbours is tempered by a repulsion of (similarly charged) next nearest neighbours.
Index pages curate the most relevant extracts from our library of academic textbooks. They’ve been created using an in-house natural language model (NLM), each adding context and meaning to key research topics.
