By evaporating a solution containing free sulphuric acid in a vacuum, the hepta-hydrated salt first separates, then the penta-, and then a tetra-hydrate, FeSO44H2O, isomorphous with manganese sulphate.
The discovery by Brebner of the specific identity of Haplospora globosa and Scaphospora speciosa marks an important step in the advance of our knowledge of the group. Three kinds of reproductive organs are known: first, sporangia, which each give rise to a single tetra-, or multi-nucleate non-motile, probably asexual spore; second, plurilocular sporangia, which are probably antheridia, generating antherozoids; and third, sporangia, which are probably oogonia, giving rise to single uninucleate non-motile oospheres.
Quin i c acid, C 6 H 7 (OH) 4 CO 2 H (tetra -oxy.cyclohexane carboxylic acid), is found in coffee beans and in quinia bark.
In the same way it may be shown that three tri-substitution, three tetra-substitution, one penta-substitution, and one hexa-substitution derivative are possible.
In the case of tetra-substituted compounds, thirty isomers are possible when all the groups are different.
If we accept Kekule's formula for the benzene nucleus, then we may expect the double linkages to be opened up partially, either by oxidation or reduction, with the formation of di-, tetra-, or hexa-hydro derivatives, or entirely, with the production of open chain compounds.
Iodine in alkaline solution converts pyrrol into iodol (tetra-iodopyrrol), crystallizing in yellowishbrown needles, which decompose on heating.
It may also be prepared by heating tetra-bromor tetra-chlorpyrrol with potas= sium iodide in alcoholic solution (German patent, 38423, 1886).
Hydriodic acid at high temperature reduces pyrrol to pyrrolidine (tetra-hydropyrrol), C 4 H 8 NH.
These substances condense to form tetra-aminotriphenylmethane, which, on heating with acids, loses ammonia and yields diaminodihydrophenylacridine, from which benzoflavin is obtained by oxidation.
The configurations of the pentaand tetra-aldoses have been determined by similar arguments; and those of the ketoses can be deduced from the aldoses.
The slag, in order that it may have such an excess of base that this will retain the phosphoric acid as fast as it is formed by the oxidation of the phosphorus of the pig iron, and prevent it from being re-deoxidized and re-absorbed by the iron, should, according to von Ehrenwerth's rule which is generally followed, contain enough lime to form approximately a tetra-calcic silicate, 4CaO,S10 2 with the silica which results from the oxidation of the silicon of the pig iron and tri-calcic phosphate, 3CaO,P205, with the phosphoric acid which forms. The danger of this " rephosphorization " is greatest at the end of the blow, when the recarburizing additions are made.
The tetra-alkyl derivatives are liquids, the remainder being solids.
Baeyer in 1890, by heating alizarin with fuming sulphuric acid for 24-48 hours at 35-40° C., obtained a product, which after treatment with caustic soda gave a sulphuric acid ester of quinalizarin, and this after acidification and boiling was converted into quinalizarin (Alizarin Bordeaux) or 22.214.171.124 tetra-oxyanthraquinone.
In chloroform solution it combines with anhydrous oxalic acid to form a compound, Sb2C18(C204), which is to be considered as COOSbC14 tetra-chlorstibonium oxalate I (R.
On distilling trimethyl stibine with zinc methyl, antimony tetra-methyl and penta-methyl are formed.
A little hydrochloric acid, methylene diresorcin [(HO) 2 C 6 H 3] 2 CH 2, whilst with chloral hydrate, in the presence of potassium bisulphate, it yields the lactone of tetra-oxydiphenyl methane carboxylic acid (J.
A r It is reduced by the action of zinc and ammonia to diand tetra-hydroquinolines.
POLYMETHYLENES, in chemistry, cyclic compounds, the simplest members of which are saturated hydrocarbons of general formula C 7, H 2nj where n may be r to 9, and known as tri-, tetra-, penta-, hexa-, and hepta-methylene, &c., or cyclo- propane, -butane, -pentane, -hexane, -heptane, &c.: - CH 21 CH 2 CH 2 CH2.CH2 CH2 CH2 CH2?C1H,, I I H ?
These acids are obtained by the reduction of the hydrobromides of the diand tetra-hydroterephthalic acids or by the action of ethylene dibromide on disodio-butane tetracarboxylic acid.
Alkyl compounds of germanium such as germanium tetra-ethyl, Ge(C2H5)4, a liquid boiling at C., have been obtained.
Group III.: B, trivalent; Al, trivalent, but possibly also tetra-or penta-valent; Ga, divalent and trivalent; In, mono-, diand tri-valent; Tl, monovalent and trivalent..
Group VI.: 0, usually divalent, but tetravalent and possibly hexavalent in oxonium and other salts; S, Se, Te, di-, tetraand hexa-valent; Cr, di-, triand hexa-valent; Mo, W, di-, tri-, tetra-, pentaand hexa-valent.
Derivatives Tetra-derivatives x x x x x x ?