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2 Pb(NO 3) 2 → 2 PbO + 4 NO 2 + O 2 PbCO 3 → PbO + CO 2. PbO is produced on a large scale as an intermediate product in refining raw lead ores into metallic lead. The usual lead ore is galena (lead(II) sulfide). At a temperature of around 1,000 °C (1,800 °F) the sulfide is converted to the oxide: [5] 2 PbS + 3 O 2 → 2 PbO + 2 SO 2
Lead(II,IV) oxide is prepared by calcination of lead(II) oxide (PbO; also called litharge) in air at about 450–480 °C: [5] 6 PbO + O 2 → 2 Pb 3 O 4. The resulting material is contaminated with PbO. If a pure compound is desired, PbO can be removed by a potassium hydroxide solution: PbO + KOH + H 2 O → K[Pb(OH) 3]
The alpha allotrope is red-colored and has the Pb–O distance of 230 pm; the beta allotrope is yellow-colored and has the Pb–O distance of 221 and 249 pm (due to asymmetry). [5] Thanks to the similarity, both allotropes can exist under standard conditions (beta with small (10 −5 relative) impurities, such as Si, Ge, Mo, etc.).
24 PbO 2 → 2 Pb 12 O 19 + 5 O 2 Pb 12 O 19 → Pb 12 O 17 + O 2 2 Pb 12 O 17 → 8 Pb 3 O 4 + O 2 2 Pb 3 O 4 → 6 PbO + O 2. The stoichiometry of the end product can be controlled by changing the temperature – for example, in the above reaction, the first step occurs at 290 °C, second at 350 °C, third at 375 °C and fourth at 600 °C.
In aqueous solution, lead(II) hydroxide is a somewhat weak base, forming lead(II) ion, Pb 2+, under weakly acidic conditions. This cation hydrolyzes and, under progressively increasing alkaline conditions, it becomes somewhat weak acid, and it forms Pb(OH) +, Pb(OH) 2 (aqueous), Pb(OH) − 3, and other species, including several polynuclear species, e.g., Pb 4 (OH) 4+ 4, Pb 3 (OH) 2+ 4, Pb 6 O ...
As well as an anhydrous form, a monohydrate (PbC 2 O 4 •H 2 O), [5] a dihydrate (PbC 2 O 4 •2H 2 O) and a trihydrate (PbC 2 O 4 •3H 2 O) are known. The dihydrate is from the orthorhombic crystal system, with space group Pnam (number 62), with unit cell dimensions: a = 9.053 Å b = 8.036 Å and c = 7.834 Å.
Addition of hydrogen sulfide or sulfide salts to a solution containing a lead salt, such as PbCl 2, gives a black precipitate of lead sulfide. Pb 2+ + H 2 S → PbS↓ + 2 H + This reaction is used in qualitative inorganic analysis. The presence of hydrogen sulfide or sulfide ions may be tested using "lead acetate paper."
[4] [5] Plumbate salts contain either the hydrated hexahydroxoplumbate(IV) or plumbate anion [Pb(OH) 6] 2−, or the anhydrous anions PbO 2− 3 (metaplumbate) or PbO 4− 4 (orthoplumbate). [4] For example, dissolving PbO 2 in a hot, concentrated aqueous solution of potassium hydroxide forms the potassium hexahydroxoplumbate(IV) salt K 2 [Pb ...