Protoxide

Chemical Designations - Synonyms Lead monoxide Lead oxide, yellow Lead protoxide Massicot Plumbous oxide Chemical Formula PbO. 

Oxydul, n. (lower or-ous) oxide, (formerly) protoxide. -eisen, n. ferrous iron, -hydrat, n. hydrated -ous oxide (-ous hydroxide), oxydullsch, a. of lower valence, -ous, Oxydul-oxyd, n. an oxide in which the metal has a lower and a higher valence, oso-ic oxide, mixed oxide. -salz, n. lower or -ous salt. 

Thermal stabilization of polyolefins has been first demonstrated for low-molecular models-normal structure alkanes [29]. It has been shown that metallic sodium and potassium hydroxide with absorbent birch carbon (ABC) as a carrier are efficient retardants of thermal destruction of n-heptane during a contact time of 12-15 s up to the temperature of 800°C [130]. Olefins and nitrous protoxide, previously reported as inhibitors of the hydrocarbon thermal destruction, are ineffective in this conditions. 

Barium Oxide (Barium Monoxide, Baryta, Barium Protoxide, Calcined Baryta). BaO, mw 153.36 colorl or white to yelsh-white deliq powd mp 1923°, bp 2000°, d 5.72g/cc. Sol in dil acids, ethanol, methanol and w (decomps with a large amt of heat being evolved). Prepn is by thermal decompn of BaCOj under high vacuum. It is a product of the burning of the many barium compds present in pyrots and, as discussed above, it is used as an anti-barrel wear additive in proplnt compns... 

Synonyms calcined baryta barium monoxide barium protoxide. 

Synonyms nickel(ll) oxide nickelous oxide green nickel oxide nickel protoxide. 

Synonyms stannous oxide tin monoxide tin protoxide Uses... 

Lead Oxide, Yellow, or Litharge (Lead Monoxide, Lead Protoxide or Plumbous Oxide). PbO, mw 223.21, yellow to yellowish-red, heavy, odorless pdr or minute, cryst scales mp 888°, bp (vol at red heat) d 9.53g/cc insol in w, ale sol in acet ac, dil nitric acid, in warm solns of fixed alkali hydroxides. It may be prepd in the lab by heating Pb nitrate, carbonate or hydroxide commercially, it is made by heating Pb to a temp considerably above its mp and continually skimming off the litharge produced. It is used in some primer compns... 

A still more intense degree of cold may bo attained by the rapid evaporation of liquids, such as bisulphide of carbon, ether, protoxide of nitrogen, and solid carbonic acid gas. By employing a bath of carbonic acid and ether in vacua, Faraday reduced the temperature... 

The Venetian contains also traces of magnesia and phosphoric or boracic acid the crystals appear disseminated through the mass, which is of a yellow tint, and transparent in thin sheets. The tin and iron obviously assist in the formation" of the crystals of metallic copper, after which the tin becomes silicate of the protoxide, otherwise the glass would become opaque. 

The oxide of lead which is used in the manufacture of crystal, is sot the protoxide commonly known as massicot, and represented by the formula Pb O, but minium, which is a sesquioxide, Pba 0 for, as Bahru el remarks, one may depend on tho latter net being mixed with metallic lead, which almost necessarily happens with the massicot of commerce. The object of employing oxide of lead in this kind of glass is to increase the density, and, consequently, tho refractive power, which gives the glass a peculiar lustre or brilliancy. 

The chemionl changes observed in the devitrification of iotlU-glasi consist, therefore,—1st. In-the loss of ft part or the whole of the -potassa. -2nd. In the passing of a part or the whole of the protoxide of iron and of manganese to the state of sesquioxides. 3rd. In the formation of one or mors definite and crystallized silicates, by means of tbe remaining products. 

It must, however, be used sparingly for an excess of it produces a compound of silicic acid with sesquioxide of manganese, which communicates a lilac or amethystine color to tho glass. The approved remedy for this, when the error has been committed, is to stir up the colored mass with a wooden pole, which reduces the sesquioxide to the protoxide, and the lilac color disappears. 

Green may be produced either by protoxide of iron, protoxide of copper—Cn 0—or oxide of chromium— Cra Oj. Tho tint produced by the Erst of these substances has little brilliancy. The oxide of copper yields... 

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