Compounds ionic oxides

A 5.025-g sample of calcium is burned in air to produce a mixture of two ionic compounds, calcium oxide and calcium nitride. Water is added to this mixture. It reacts with calcium oxide to form 4B32 g of calcium hydroxide. How many grams of calcium oxide are formed How many grams of calcium nitride ... 

FIGURE 5.46 (a) When a metal s cations are displaced by a blow from a hammer, the mobile electrons can immediately respond and follow the cations to their new positions, and consequently the metal is malleable, (b) This piece of lead nas been flattened by a hammer, whereas crystals of the orange-colored ionic compound leaddl) oxide have shattered. 

Oxidation state is a frequently used (and indeed misused) concept which apportions charges and electrons within complex molecules and ions. We stress that oxidation state is a formal concept, rather than an accurate statement of the charge distributions within compounds. The oxidation state of a metal is defined as the formal charge which would be placed upon that metal in a purely ionic description. For example, the metals in the gas phase ions Mn + and Cu are assigned oxidation states of +3 and +1 respectively. These are usually denoted by placing the formal oxidation state in Roman numerals in parentheses after the element name the ions Mn- " and Cu+ are examples of manganese(iii) and copper(i). 

A normal oxide is a binary (two element) compound containing oxygen in the -2 oxidation state. BaO is an example of an ionic oxide and S02 is an example of a molecular (covalent) oxide. 

The oxidation of organic compounds by water-soluble inorganic oxidants is often made difficult not only by the insolubility of the organic substrate in water, but also by the susceptibility of many of the miscible non-aqueous solvents to oxidation. Solubilization of the ionic oxidant into solvents such as benzene, chloroform, dichloromethane or 1,2-dichlorobenzene, by phase-transfer catalysts obviates these problems, although it has been suggested that dichloromethane should not be used, as it is also susceptible to oxidation [1]. 

The two magnesium ions with a positive charge are attracted to the two negatively charged oxygen atoms to form the ionic compound magnesium oxide, MgO. 

A In fully ionic oxides the oxygen species present is O therefore the oxidation slate of the oxygen is equal to the charge, i.e. 2. This value is taken to he the oxidation stale of oxygen in compounds that are not necessarily ionic. The oxide ion has the fully occupied valence orbitals equivalent to the electronic eonliguralion ol neon. 2j 2p<. the Group IS element at the end of the same period. 

Vanadium trichloride or tribromide reacts with thioethers giving [VX3L2] (X = C1 or Br L = SMe2, tetrahydrothiophene or SEt2).288,289 The complex with di-n-propyl sulfide could not be isolated.288 These compounds are oxidized very easily. Solubility, molecular weights and conductance show that they are monomeric and non-ionic. Dipole moments, IR and electronic spectra are consistent with trans trigonal bipyramidal structures. 

An aluminum ion carries a 3+ charge, and an oxide ion carries a 2— charge. Together, these ions make the ionic compound aluminum oxide, AI203, the main component of such gemstones as rubies and sapphires. Figure 6.10 illus-... 

What is the chemical formula for the ionic compound magnesium oxide ... 

Because of the high price of TPAP, research is being made in order to develop new protocols and modified reagents that allow the recovery of perruthenate—present as TPAP or in other compounds—after oxidation of alcohols. Proposed alternatives include employing TPAP in the presence of ionic salts,62 on an Amberlist anion exchange resin63 or on a silicate.69b,c,d... 

In ionic binary compounds, the oxidation number is the charge per atom. 

Silicon, diamond, and metal deposition are all examples of elemental deposition. Compounds, particularly oxides, are also deposited by chemical vapor deposition. Some of the important oxides deposited as thin films include SiC>2, BaTiC>3, LiNbC>3, YBa2Cu30,. indium-doped SnC>2, and LiCoC>2. These materials have properties such as superconductivity or lithium ionic conductivity that make their production as thin films a much-studied area of research. If the oxide is to be deposited on the bare metal (e.g., depositing SiC>2 onto Si), chemical vapor deposition is not really needed. Controlling the oxygen partial pressure and temperature of the substrate will produce the oxide film Whether the film sticks to the substrate is another question The production of SiC>2 films on Si is an advanced technology that the integrated-circuit industry has relied on for many years. Oxide films on metals have been used to produce beautiful colored coatings as a result of interference effects (Eerden et al., 2005). 

Because intermetallic systems undoubtedly display certain special features that follow from their metallic binding forces, considerable importance attached to the growing evidence that the chalcogenides, the essentially ionic oxides, the nitrides, and other representative binary compounds of the transition metals were, not infrequently, both variable and irrational in composition. Schenck and Ding-mann s equilibrium study of the iron-oxygen system (39) was notable in this connection They showed that stoichiometric ferrous oxide, FeOi 000, the oxide of an important and typical valence state, did not exist. It lay outside the broad existence field of a nonstoichiometric phase. It is, perhaps, still not certain... 

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