IV Oxide

Lead(IV) oxide, PbOj. Chocolate brown (electrolytic oxidation of Pb(II) salts). Used as an oxidizing agent. [Pg.238]

Titanium IV) oxide, T1O2. See titanium dioxide. Dissolves in concentrated alkali hydroxides to give titanates. Mixed metal oxides, many of commercial importance, are formed by TiOj. CaTiOj is perovskite. BaTiOa, per-ovskite related structure, is piezoelectric and is used in transducers in ultrasonic apparatus and gramophone pickups and also as a polishing compound. Other mixed oxides have the il-menite structure (e.g. FeTiOj) and the spinel structure (e.g. MgjTiO ). [Pg.400]

The gradual increase in electropositive character down the group is clearly shown in that, unlike both carbon and silicon, germanium very readily dissolves in both concentrated nitric and sulphuric acids the hydrated germanium(IV) oxide is produced ... [Pg.169]

Concentrated nitric acid, however, is an oxidising agent and tin reacts to give hydrated tin(IV) oxide in a partly precipitated, partly colloidal form, together with a small amount of tin(II) nitrate, Sn(N03)2 ... [Pg.170]

Ordinary white tin is not attaeked by air at ordinary temperatures but on heating in air it forms tin(IV) oxide, Sn02. [Pg.172]

Finely divided lead, when heated in air, forms first the lead(II) oxide, litharge , PbO, and then on further heating in an ample supply of air, dilead(II) lead(IV) oxide, red lead , Pb304. Lead, in a very finely divided state, when allowed to fall through air, ignites and a shower of sparks is produced. Sueh finely divided powder is said to be pyrophoric . It can be prepared by carefully heating lead tartrate. [Pg.172]

Germanium(IV) oxide occurs in two forms one has a rutile lattice and melts at 1359 K whilst the other has a quartz lattice and a melting point of 1389 K. It can be prepared by oxidation of germanium using, for example, concentrated nitric acid, or by the hydrolysis of germanium tetrachloride ... [Pg.191]

Tin(II) oxide is a dark-coloured powder which oxidises spontaneously in air with the evolution of heat to give tin(IV) oxide, SnO, ... [Pg.192]

Tin(IV) oxide occurs naturally, clearly indicating its high stability. It can be prepared either by heating tin in oxygen or by heating the... [Pg.192]

Tin(IV) oxide is insoluble in water, but if fused with sodium hydroxide and the mass extracted with water, sodium hexahydroxo-stannate(IV) is formed in solution ... [Pg.193]

If a dilute acid is added to this solution, a white gelatinous precipitate of the hydrated tin(IV) oxide is obtained. It was once thought that this was an acid and several formulae were suggested. However, it now seems likely that all these are different forms of the hydrated oxide, the differences arising from differences in particle size and degree of hydration. When some varieties of the hydrated tin(IV) oxide dissolve in hydrochloric acid, this is really a breaking up of the particles to form a colloidal solution—a phenomenon known as peptisation. [Pg.193]

Lead(IV) oxide can be prepared by the action of an alkaline chlorate(I) solution on a solution of a lead(II) salt. The reaction can be considered in two stages ... [Pg.194]

Lead(IV) oxide is also obtained when red lead , Pb304 (see below), is treated with dilute nitric acid ... [Pg.194]

When heated above 600 K lead(IV) oxide decomposes into the more stable lead(II) oxide and oxygen ... [Pg.194]

Lead(IV) oxide is found to have a considerable oxidising power, again indicating that the oxidation state +2 is generally more stable for lead than oxidation state +4. Concentrated hydrochloric acid, for example, reacts with PbO at room temperature to form lead(II) chloride and chlorine ... [Pg.194]

Red lead is insoluble in water. Like lead(II) oxide it can readily be reduced to lead. The structure of the solid, as the systematic name suggests, consists of two interpenetrating oxide structures, in which each Pb atom is surrounded octahedrally by six oxygen atoms, and each Pb" by three (pyramidal) oxygen atoms, the oxygen atoms being shared between these two units of structure. With dilute nitric acid the lead(ll) part dissolves, and the lead(IV) part precipitates as lead(IV) oxide ... [Pg.195]

Lead(IV) chloride is formed from cold concentrated hydrochloric acid and lead(IV) oxide as described earlier. It readily evolves chlorine by the reversible reaction ... [Pg.200]

On the industrial scale oxygen is obtained by the fractional distillation of air. A common laboratory method for the preparation of oxygen is by the decomposition of hydrogen peroxide. H Oj, a reaction catalysed by manganese(IV) oxide ... [Pg.260]

It decomposes exothermically to oxygen, a reaction which can be explosive. Even dilute ozone decomposes slowly at room temperature the decomposition is catalysed by various substances (for example manganese(IV) oxide and soda-lime) and occurs more rapidly on heating. [Pg.264]

IV) oxide, the latter being used in the eommon laboratory preparation of oxygen from hydrogen peroxide (p. 260. ... [Pg.280]

Alternatively a mixture of almost any solid chloride and manganese-(IV) oxide will yield chlorine when warmed with concentrated sulphuric acid. These are the most common laboratory methods but there are many others. [Pg.317]

In the laboratory, bromine is prepared by oxidation of bromide ion the oxidation is carried out by mixing solid potassium bromide with manganese(IV) oxide and distilling with concentrated sulphuric acid ... [Pg.318]

Iodine is rarely prepared in the laboratory the method used is the oxidation of an iodide by manganese(IV) oxide and sulphuric acid, for example with sodium iodide ... [Pg.319]

The decomposition of potassium chlorate(V) is catalysed by manganese(IV) oxide, Mn02, and oxygen is evolved on heating the mixture below the melting point of the chlorate(V). [Pg.340]

If a chloride is heated with manganese(IV) oxide and concentrated sulphuric acid, chlorine is evolved. [Pg.349]

Manganese is the third most abundant transition metal, and is widely distributed in the earth s crust. The most important ore is pyrolusite, manganese(IV) oxide. Reduction of this ore by heating with aluminium gives an explosive reaction, and the oxide Mn304 must be used to obtain the metal. The latter is purified by distillation in vacuo just above its melting point (1517 K) the pure metal can also he obtained by electrolysis of aqueous manganese(II) sulphate. [Pg.384]

Manganese(IV) oxide is the only familiar example of this oxidation state. It occurs naturally as pyrolusite, but can be prepared in an anhydrous form by strong heating of manganese(II) nitrate ... [Pg.387]

Manganese(IV) oxide is a dark-brown solid, insoluble in water and dilute acids. Its catalytic decomposition of potassium chlor-ate(V) and hydrogen peroxide has already been mentioned. It dissolves slowly in alkalis to form manganates(lW), but the constitution of these is uncertain. It dissolves in ice-cold concentrated hydrochloric acid forming the complex octahedral hexachloromangan-ate(IV) ion ... [Pg.387]

An oxidation which can be used to estimate the amount of man-ganese(IV) oxide in a sample of pyrolusite is that of ethanedioic acid ... [Pg.388]

Examples P2O5, diphosphorus pentaoxide or phosphorus)V) oxide Hgj, mercury(I) ion or dimercury(2-l-) ion K2[Fe(CN)g], potassium hexacyanoferrate(II) or potassium hexacyanofer-rate(4—) PbJPb 04, dilead(II) lead(IV) oxide or trilead tetraoxide. [Pg.216]

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