Chemistry
Properties of Transition Metals
Transition metals are characterized by their ability to form multiple oxidation states, exhibit variable coordination numbers, and form colorful compounds due to d-d electronic transitions. They often act as catalysts in chemical reactions due to their ability to undergo redox reactions. Transition metals also have high melting and boiling points, and are known for their strength and durability.
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10 Key excerpts on "Properties of Transition Metals"
eBook - PDF- Edward J. Neth, Paul Flowers, Klaus Theopold, Richard Langley, William R. Robinson(Authors)
- 2019(Publication Date)
- Openstax(Publisher)
INTRODUCTION CHAPTER 19 Transition Metals and Coordination Chemistry 19.1 Occurrence, Preparation, and Properties of Transition Metals and Their Compounds 19.2 Coordination Chemistry of Transition Metals 19.3 Spectroscopic and Magnetic Properties of Coordination Compounds We have daily contact with many transition metals. Iron occurs everywhere—from the rings in your spiral notebook and the cutlery in your kitchen to automobiles, ships, buildings, and in the hemoglobin in your blood. Titanium is useful in the manufacture of lightweight, durable products such as bicycle frames, artificial hips, and jewelry. Chromium is useful as a protective plating on plumbing fixtures and automotive detailing. In addition to being used in their pure elemental forms, many compounds containing transition metals have numerous other applications. Silver nitrate is used to create mirrors, zirconium silicate provides friction in automotive brakes, and many important cancer-fighting agents, like the drug cisplatin and related species, are platinum compounds. The variety of properties exhibited by transition metals is due to their complex valence shells. Unlike most main group metals where one oxidation state is normally observed, the valence shell structure of transition metals means that they usually occur in several different stable oxidation states. In addition, electron transitions in these elements can correspond with absorption of photons in the visible electromagnetic spectrum, leading to colored compounds. Because of these behaviors, transition metals exhibit a rich and fascinating chemistry. 19.1 Occurrence, Preparation, and Properties of Transition Metals and Their Compounds Transition metals are defined as those elements that have (or readily form) partially filled d orbitals. As shown in Figure 19.2, the d-block elements in groups 3–11 are transition elements.
eBook - PDF- Young, William Vining, Roberta Day, Beatrice Botch(Authors)
- 2017(Publication Date)
- Cengage Learning EMEA(Publisher)
AlbertSmirnov/iStockphoto.com 24 The Transition Metals Unit Outline 24.1 Properties of the Transition Metals 24.2 Isolation from Metal Ores 24.3 Coordination Compounds: Structure and Isomerism 24.4 Coordination Compounds: Bonding and Spectroscopy In This Unit… We have used our understanding of basic principles of chemistry to undertake brief explorations of the properties and reactivity of organic compounds and main-group elements, particularly those of the p -block elements. We now turn to the more complex chemistry of the transition metals, which consist of the metals found in Groups 3B-2B (Groups 3-12 in the IUPAC numbering system) of the periodic table. These elements play crucial roles in the manufacture of modern materials and in many important biological processes. In this unit we will examine how the metals are formed from their ores, used in alloys, and used to form coordination complexes, which are special types of Lewis acid–base compounds. Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-300 Unit 24 The Transition Metals 774 24.1 Properties of the Transition Metals 24.1a General Characteristics of Transition Metals Transition metals are traditionally defined as the elements in Groups 3B-2B (3-12) of the periodic table. However, IUPAC defines transition elements as those elements whose atoms have partially filled d orbitals in their neutral or cationic state. Using this definition, the elements in Group 2B—zinc, cadmium, mercury, and copernicium—are not considered transition metals. However, in this unit we will occasionally include these elements in our discussion of the chemistry of the transition metals. Interactive Figure 24.1.1 shows the elements traditionally considered to be transition metals.
eBook - PDF- William R. Robinson, Edward J. Neth, Paul Flowers, Klaus Theopold, Richard Langley(Authors)
- 2016(Publication Date)
- Openstax(Publisher)
In addition, electron transitions in these elements can correspond with absorption of photons in the visible electromagnetic spectrum, leading to colored compounds. Because of these behaviors, transition metals exhibit a rich and fascinating chemistry. Chapter 19 | Transition Metals and Coordination Chemistry 1053 19.1 Occurrence, Preparation, and Properties of Transition Metals and Their Compounds By the end of this section, you will be able to: • Outline the general approach for the isolation of transition metals from natural sources • Describe typical physical and chemical properties of the transition metals • Identify simple compound classes for transition metals and describe their chemical properties Transition metals are defined as those elements that have (or readily form) partially filled d orbitals. As shown in Figure 19.2, the d-block elements in groups 3–11 are transition elements. The f-block elements, also called inner transition metals (the lanthanides and actinides), also meet this criterion because the d orbital is partially occupied before the f orbitals. The d orbitals fill with the copper family (group 11); for this reason, the next family (group 12) are technically not transition elements. However, the group 12 elements do display some of the same chemical properties and are commonly included in discussions of transition metals. Some chemists do treat the group 12 elements as transition metals. Figure 19.2 The transition metals are located in groups 3–11 of the periodic table. The inner transition metals are in the two rows below the body of the table. The d-block elements are divided into the first transition series (the elements Sc through Cu), the second transition 1054 Chapter 19 | Transition Metals and Coordination Chemistry This OpenStax book is available for free at http://cnx.org/content/col12012/1.7 series (the elements Y through Ag), and the third transition series (the element La and the elements Hf through Au).
eBook - PDF- Paul Flowers, Klaus Theopold, Richard Langley, William R. Robinson(Authors)
- 2015(Publication Date)
- Openstax(Publisher)
In addition, electron transitions in these elements can correspond with absorption of photons in the visible electromagnetic spectrum, leading to colored compounds. Because of these behaviors, transition metals exhibit a rich and fascinating chemistry. Chapter 19 | Transition Metals and Coordination Chemistry 1051 19.1 Occurrence, Preparation, and Properties of Transition Metals and Their Compounds By the end of this section, you will be able to: • Outline the general approach for the isolation of transition metals from natural sources • Describe typical physical and chemical properties of the transition metals • Identify simple compound classes for transition metals and describe their chemical properties Transition metals are defined as those elements that have (or readily form) partially filled d orbitals. As shown in Figure 19.2, the d-block elements in groups 3–11 are transition elements. The f-block elements, also called inner transition metals (the lanthanides and actinides), also meet this criterion because the d orbital is partially occupied before the f orbitals. The d orbitals fill with the copper family (group 11); for this reason, the next family (group 12) are technically not transition elements. However, the group 12 elements do display some of the same chemical properties and are commonly included in discussions of transition metals. Some chemists do treat the group 12 elements as transition metals. Figure 19.2 The transition metals are located in groups 3–11 of the periodic table. The inner transition metals are in the two rows below the body of the table. The d-block elements are divided into the first transition series (the elements Sc through Cu), the second transition 1052 Chapter 19 | Transition Metals and Coordination Chemistry This OpenStax book is available for free at http://cnx.org/content/col11760/1.9 series (the elements Y through Ag), and the third transition series (the element La and the elements Hf through Au).
eBook - PDF- William W. Porterfield(Author)
- 2013(Publication Date)
- Academic Press(Publisher)
Part Transition-Metal Compounds IV This page intentionally left blank The Properties of Transition Metals and Their Compounds Most of our discussion thus far has dealt with the structure and reactions of main- group elements— elements having s and p valence electrons only. The remainder of the book will be devoted to the chemistry of transition elements, those having valence d and/electrons. This perhaps seems a rather trivial distinction to make, but in fact this single change opens up entirely new types of orbital overlap and bonding, allowing the formation of compounds with quite different chemical properties. The inorganic chemist’s attraction has focused particularly on ^elec-tron transition elements, usually called simply the transition metals. The ^-elec-tron transition elements are usually known as lanthanides or rare earths; those with 5/ valence electrons are known as actinides. This chapter deals primarily with the J-electron transition metals, and makes a few comparisons with lan-thanides and actinides. We shall look at the nature of d orbitals and electrons, the bonding of these electrons in metals, the nature of the metals themselves, typical ionic lattices for the d block metals, and the basis for superconductor behavior in these lattices. Since the distinction between main-group metals and transition metals de-pends on the orbitals occupied, there is little difference in the properties of the pre-dominantly ionic compounds of the two groups. Ionic bonding, of course, can be described quite well on a “billiard-ball” basis without explicitly considering or-bitals or overlap. Table 10.1 suggests that the predominantly ionic transition-metal fluorides have much the same physical properties as the main-group ionic fluorides with the same metal charge and thus comparable lattice and solvation energies. For both groups, the chlorides are significantly less ionic, but the parallels are still quite strong.
eBook - ePubChemistry
With Inorganic Qualitative Analysis
- Therald Moeller(Author)
- 2012(Publication Date)
- Academic Press(Publisher)
Among the transitions that may occur are promotion of electrons from the d level to the higher s level or from the lower t 2 g to the higher e g energy level in complexes (called crystal-field transitions). There are some exceptions—for example, titanium(IV) compounds are usually colorless because the electrons are all paired and are not readily raised to higher energy levels. Many colorless ions are also found among the compounds of the second and third transition series, for example, [Pd(NH 3) 4 ] 2+ and [Pt(NH 3) 6 ] 4+. In such compounds the electrons are so tightly held that they are not readily raised to orbitals of higher energy. Another general property of d transition metals and their compounds is their high catalytic activity, which is usually due to the ease with which electrons are lost and gained or moved from one shell to another. Some typical applications of this property are the use of nickel as a hydrogenation catalyst, the ability of V 2 O 5 to serve as a catalyst in the contact process for the manufacture of sulfuric acid, and the use of MnO 2 in the catalytic decomposition of potassium chlorate. The catalytic activity of the transition metals and their compounds gives them great importance in the chemical industry. Chemists are always attempting to modify the rates of reactions by catalytic action. In many cases, the mechanism by which a well-known catalyst operates has not yet been discovered, and there is continuous effort to better understand how catalysts behave. In the meantime, empirical research is carried on in an attempt to improve the catalysts that are available or to find new and better ones
- P N Butcher, Lu Yu(Authors)
- 1995(Publication Date)
- World Scientific(Publisher)
145 On the Electronic Structure and Related Physical Properties of 3d Transition Metal Compounds G.A. Sawatzky Department of Applied and Solid State Physics, Materials Science Center, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherland 1. Introduction Compounds of the 3d transition metals exhibit an astonishing variety of physical properties both electrical and magnetic. 1 3 The electric properties range from large band gap insulators (V 2 0 5 , Cr 2 0 3 , a -F e ^ ) and ferroelectrics (BaTi0 3 ) to semiconductors (Cu 2 0, FeS 2 , MnS) and via semiconductor metal transitions (VO^ V 2 0 3 , Fe30 4 , Ti 2 0 3 ) to metals (Cr0 2 , NiS, CuS) and even superconductors (La 2 . x Ba x Cu0 4 , YBa 2 Cu 3 0 7 ).
eBook - ePubUnderstanding Bioanalytical Chemistry
Principles and Applications
- Victor A. Gault, Neville H. McClenaghan(Authors)
- 2013(Publication Date)
- Wiley(Publisher)
3
Transition metals in health and disease
Transition metals comprise part of the d-block (groups 3–11) or middle portion of the Periodic Table of elements (see Appendix 2). The term transition metal arose as a result of their position in the Periodic Table and how they represent the transition between group 2 through to group 12 elements. Transition metals are widely distributed throughout the earth and oceans, and play extremely important roles in nature. While transition metals are considered ‘trace elements’ in mammals, this by no means reflects their importance, and these metals play a key, often essential, role in many biological processes and, in particular, the catalysis of physiological enzymatic reactions. This chapter considers some of the core features of transition metals and their role in the regulation of normal physiological processes and the pathogenesis of disease.Learning Objectives
- To describe and explain the structure and characteristics of key transition metals.
- To outline and discuss the importance of transition metals in physiological processes.
- To appreciate and convey the role of transition metals in disease processes.
- To give examples to illustrate the therapeutic implications of transition metals.
- To demonstrate knowledge of how transition metals are determined in nature.
3.1 Structure and characteristics of key transition metals
By the IUPAC (International Union of Pure and Applied Chemistry) definition, a transition metal is an element, an atom of which contains an incomplete d shell, or that gives rise to a cation with an incomplete d shell. Transition metals have a total of nine atomic orbitals, but only some of these are used for bonding to ligands . Coordination number denotes the number of donor atoms associated with the central atom and dictates the shape, or stereochemistry , of the coordination complex
eBook - PDFThe Chemistry of the Metallic Elements
The Commonwealth and International Library: Intermediate Chemistry Division
- David J. Steele, J. E. Spice(Authors)
- 2017(Publication Date)
- Pergamon(Publisher)
CHAPTER 8 The Transition Elements: their General Chemistry IN THE long version of the Periodic Table, between Groups Ila and Illb, there lies a block of elements known collectively as the transition elements. Precisely which elements are defined as transitional is, to a certain extent, a matter for personal opinion. There is general agreement that the term includes those elements having an incomplete d-or/-subshell of electrons. It will be seen from Table 8.1 that such a definition embraces all the elements in the block except the Group lib, the zinc triad, for these elements represent the stage where the inner shell is just filled. They there-fore show none of the characteristic properties associated with incomplete electron subshells. They have outer electronic structures similar to Group Ila: complete inner shells and two ^-electrons in the outer shell. For this reason there are marked similarities in the chemistry of the elements in the two Groups. The possession of a complete */-subshell bestows upon these elements properties which made it convenient to discuss them in the previous chapter. Elements of Group lb in oxidation states other than +1 (i.e. Cu +2 , Ag +2 , Au +3 ), in which the rf-electrons are used in bond formation, fall properly under the definition of transi-tional and will be discussed in this chapter. Certain other features of both Groups lb and lib will again be mentioned here to demonstrate transitional characteristics or to emphasise their disappearance when the rf-subshell is complete. The elements in Group Ilia, scandium, yttrium, lanthanum, and actinium have two ^-electrons in their outer shell and one ^/-electron in the penultimate shell; these three electrons are easily lost and the chemistry of the elements, especially scandium, is that of their tripositive ions, i.e. Sc(atom) ► Sc + + + +3e 3s 2 3p 6 3d 1 As 2 3s 2 3p 6 Scandium shows no transitional characteristics and might, with some justification, be 84
- R.A. Mackay, W. Henderson(Authors)
- 2017(Publication Date)
- CRC Press(Publisher)
HAPTER 13 The Transition Metals: General Properties and Complexes13.1 INTRODUCTION TO THE TRANSITION ELEMENTS13.2 THE TRANSITION ION AND ITS ENVIRONMENT: LIGAND FIELD THEORY13.3 LIGAND FIELD THEORY AND OCTAHEDRAL COMPLEXES13.4 COORDINATION NUMBER FOUR13.5 STABLE CONFIGURATIONS13.6 COORDINATION NUMBERS OTHER THAN FOUR OR SIX13.7 EFFECT OF LIGAND ON STABILITY OF COMPLEXES13.8 ISOMERISM13.9 MECHANISMS OF TRANSITION METAL REACTIONS13.10 STRUCTURAL ASPECTS OF LIGAND FIELD EFFECTS13.11 SPECTRA OF TRANSITION ELEMENT COMPLEXES13.12 π BONDING BETWEEN METAL AND LIGANDSPROBLEMS13.1 Introduction to the transition elements
The elements of the transition block are those with d electrons and incompletely filled d orbitals. The zinc Group, with a filled d10 configuration in all its compounds, is transitional between the d block and the p elements and is discussed later.The Groups of the d block contain only three elements and correspond to the filling of the 3d, 4d and 5d shells respectively. In between the 4d and 5d levels is interposed the first f level, the 4f shell, which fills after lanthanum. It has already been seen (Chapter 11 ) that the occupation of this level is accompanied by a gradual decrease in atomic and ionic radius from La to Lu and the total lanthanide contraction is approximately equal to the normal increase in size between one Period and the next. The result is that in the transition Groups there is the normal increase of about 20 pm in radius between the first and second members (filling the 3d and 4d shells), but the expected increase between the second and third members is just balanced by the lanthanide contraction so that these two elements are almost identical in size. This effect is illustrated by the radii given in Table 13.1
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