Insertion compounds

Many inorganic solids are capable of undergoing insertion reactions with small ions such as Li, and Na. The host solid in these reactions undergoes reduction in order to those of the respective hosts, with the inserted cation occupying formerly empty sites of the host. 

The class of layered transition-metal dichalcogenides has been of great interest because of their varied electronic properties and chemical reactions. Most compounds of this may be prepared by stoichiometric reactions of the elements above 500°. However, the highest vanadium sulfide that can be made in this manner is VjSg. An amorphous VSj has been prepared by the metathetical reaction of LijS and VCl4. The method presented here allows preparation of polycrystalline VS with the CdU structure.  

The LiVSj is prepared from an intimate mixture of V2O5 (0.094 g, 0.05 mol) and Li2C03 (3.694 g, 0.05 mol). The mixture is placed in a vitreous carbon boat inside a quartz tube in a tube furnace. The tube is connected to a two-way inlet valve for argon (or another inert gas) and hydrogen sulfide. Gas 

A solution of O.IM I2 is prepared from freshly sublimed 12 and acetonitrile distilled from P4O10- The solution is standardized by titration with a standard aqueous thiosulfate solution to the disappearance of the I2 color. Addition of iodide and/or starch gives no color enhancement in acetonitrile. 

Combustion Anal. Calcd. for VS2 V, 44.3. Found, 44.5. Atomic absorption for Li gives 180 ppm. X-ray fluorescence shows no iodine. 

Generalized Equation (10.1) is applicable to all electrodes, but the finer mechanism of lithium insertion and extraction is different in different cases. 

In the case of lithium insertion into the oxide material of the positive electrode (e.g., Li(i j()Co02) the lithium ion is embedded into the crystal lattice. Herewith, the valency of the main metal (here, cobalt) decreases by one. In fact, under the operation of such an electrode, that is, in the case of the following process  

Electrochemical Power Sources Batteries, Fuel Cells, and Supercapacitors, First Edition. Vladimir S. Bagotsky, Alexander M. Skundin, and Yurij M. Voltkovich 2015 John Wiley Sons, Inc. Published 2015 by John Wiley Sons, Inc. 

When lithium is inserted into such materials as lithium iron phosphate, a separate phase of lithium iron phosphate is formed that is insoluble in the initial lithium iron phosphate  

no variable composition compounds are formed at an increase in the lithiation degree it is the ratio of the amounts of the FeP04 and LiFeP04 phases that changes and the potential remains unchanged in the course of charging or discharge. 

Submitted by D. W. MURPHY and S. M. ZAHURAK Checked by C. J. CHENt and M. GREENBLATTt 

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U. von Sacken, Q. Zhong, Tao Zheng, and J.R. Dahn, Phenolic Resin Precursor Pregraphitic Carbonaceous Insertion Compounds and Use as Anodes in Rechargeable Batteries, Canadian Patent Application 2,146,426... 

Recently, lithium-ion inserted compounds have been investigated as new anodes. These compounds have the possibility of... 

Bruce PG, Irvine ITS (2001) Insertion Compounds. In Encyclopedia of Materials Science and Technology, Elsevier Science Ltd Oxford ISBN 0-08-0431526, pp. 4115-4121 SchoUhom R (1980) Reversible topotactic redox reactions of solids by electron/ion transfer. Angew Chem Int Ed Engl 19 983-1003... 

Insertion (intercalation) compounds. Insertion compounds are defined as products of a reversible reaction of suitable crystalline host materials with guest molecules (ions). Guests are introduced into the host lattice, whose structure is virtually intact except for a possible increase of some lattice constants. This reaction is called topotactic. A special case of topotactic insertion is reaction with host crystals possessing stacked layered structure. In this case, we speak about intercalation (from the Latin verb intercalare, used originally for inserting an extra month, mensis intercalarius, into the calendar). 

Thermolysis of 12 with frans-cinnamaldehyde afforded the insertion compound 19, formed through the di-insertion of two carbonyl ligands into the C—Si bond of 12. The reaction of 12 with fumaronitrile yielded the cyclization product 20. X-ray study revealed 20 to be a cyclization product which contains two types of disilyl moieties, imino and N,N-bis(silyl)amino, which are connected by a five-membered ring. 

Insertion electrodes I Atomic and electronic structure of the hosts and their insertion compounds... 

Heated direct insertion compounds volatile and stable ... 

As discussed below, there are problems with morphological changes and passivation reactions at lithium metal negative electrodes in secondary cells, which reduce cycle life and the practical energy density of the system, and may in some circumstances introduce safety hazards. A more recent development involves the replacement of the lithium metal anode by another insertion compound, say C Dm. In this cell, the electrochemical process at the negative side, rather than lithium plating and... 

Transition metal nitrides and carbides can be described, generally speaking, as insertion compounds of nitrogen or carbon in the metal network.1 In fact, strong metal-nonmetal interactions exist which induce structural modifications.1,2 These compounds form a class of materials with unique physical3,4 and catalytic1,5,6 properties. The term platinoids has been used to illustrate their potential in reactions traditionally catalysed by noble metals. 

Silicon-carbon and silicon-nitrogen multiply bonded compounds 1019 insertion compound 712 (55% yield) (equation 236). 

The term insertion compound is used for solids where atoms or ions enter a three-dimensional framework without disrupting its essential structure. Many oxide bronzes are of this type, based on transition metal oxides with inserted alkali or other electropositive metals. 

Many plastic materials are not compatible with nonaqueous solutions. The plastics themselves or the plasticizers may dissolve into the solution and contaminate it. In addition, active metals (including their alloys or low potential insertion compounds such as Li—C) are incompatible with glass and any plastic materials which contain F or Cl, such as Teflon and PVC. Hence, for nonaqueous systems which do not contain active metal electrodes, glass or Teflon may be the most desirable cell construction materials. Cell parts that must be in contact with active metals should, however, be made of polyethylene or polypropylene. 

Wagemaker M, Mulder FM, Van der Ven A. The Role of Surface and Interface Energy on Phase Stability of Nanosized Insertion Compounds. Adv Mater. 2009 21(25-26) 2703-9. 

As expected from the Li-PDOS in Table 3.2, the net charge of Li is more than 0.7. This means that the nature of the V-O bond is hardly affected by the presence of Li. The fact that Mulliken s charge of Li is almost fully ionized is contrary to the widely accepted picture of Li-inserted compounds, and should be a very important factor in determining the high OCV for Li+ ions. One of the parameters that determine the redox reaction energy is the covalent bonding of the electrons at a transition metal cation. 

Palladium-catalyzed double-silylation reactions of 3,4-carboranylene-l,l,2,2-tetraethyl-l,2-disilacyclobut-3-ene 124, obtained from the reaction of 1,2-dilithiated o-carborane with 1,2-dichlorotetraethyldisilane, have been described <20010M5537>. Thus, the reaction of 124 with /ram-cinnamaldchydc in the presence of Pd(PPh3>4 yielded the insertion compound 125, whose structure was determined by single crystal X-ray crystallography (Equation 18). 

Although the study of sulfur dioxide-transition metal coordination chemistry is an area of relatively recent intensive pursuit, structural information now spans a large number of stereochemically distinct coordination situations. The types of M-SO2 binding which have been identified, excluding insertion compounds and compounds containing SO2 bridging metal centers, are shown in Fig. 1. Several examples of complexes containing each type... 

Fig. 28. [Q>Fe(C0)j2(S02), which contains an unsupported M-SOy-M bridge. (Reprinted, with permission, from Crystallographie Studies on Sulfur Dioxide Insertion Compounds. IV. Structure of -(Sulfur dioxide)-bis( -cyclopen-tadienyldicarbonyliron). Including the Location an Refinement of Hydrogen Atoms, Churchill,...

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