Online Encyclopedia

Search over 40,000 articles from the original, classic Encyclopedia Britannica, 11th Edition.

ERYTHRITE

Online Encyclopedia
Originally appearing in Volume V09, Page 758 of the 1911 Encyclopedia Britannica.
» Make a correction to this article.
» Add information or comments to this article.
Spread the word: del.icio.us del.icio.us it!

ERYTHRITE , the name given to (I) a See also:

mineral composed of a hydrated See also:cobalt arsenate, nd (2) in See also:chemistry, a tetrahydric See also:alcohol. (I) The mineral erythrite has the See also:formula Co3(AsO4)2.8H2O, and crystallizes in the See also:monoclinic See also:system and is isomorphous with See also:vivianite. It sometimes occurs as beautiful radially-arranged See also:groups of blade-shaped crystals with a See also:bright See also:crimson See also:colour and brilliant lustre. On exposure to See also:light the colour and lustre deteriorate. There is a perfect cleavage parallel to the See also:plane of symmetry, on which the lustre is pearly. Cleavage flakes are soft (H=2), sectile and flexible; specific gravity 2.95. The mineral is, however, more often found as an earthy encrustation with a See also:peach-blossom colour, and in this See also:form was See also:early (1727) known as cobalt-See also:bloom ( Ger. Kobaltbliithe). The name erythrite, from ipv0pbs, " red," was given by F. S. See also:Beudant in 1382. Erythrite occurs as a product of alteration of See also:smaltite (CoAs2) and other cobaltiferous arsenides.

The finest crystallized specimens are from See also:

Schneeberg in See also:Saxony. The earthy variety has been found in Thuringia and See also:Cornwall and some other plates. (2) The alcohol erythrite has the constitutional formula HO•H2C•CH(OH)•CH(OH)•CH2OH; it is also known as erythrol, erythroglucin and phycite. It corresponds to tartaric See also:acid, and, like this substance, it occurs in four stereo-isomeric forms. The internally compensated modification, i-erythrite, corresponding to mesotartaric acid, occurs See also:free in the See also:algae Protococcus vulgaris, and as the orsellinate, erythrin, C4H6(OH)2(O•C8H203)2, in many See also:lichens and algae, especially Roccella montagnei. It has a sweet See also:taste, melts at 126°, and boils at 330. Careful oxidation withdilute nitric acid gives erythrose or tetrose, which is probably a mixture of a trioxyaldehyde and trioxyketone. Energetic oxidation gives erythritic acid and mesotartaric acid. i-Erythrite and the racemic mixture of the dextro and laevo varieties were synthesized by Griner in 1893 from divinyl.

End of Article: ERYTHRITE

Additional information and Comments

There are no comments yet for this article.
» Add information or comments to this article.
Please link directly to this article:
Highlight the code below, right click, and select "copy." Then paste it into your website, email, or other HTML.
Site content, images, and layout Copyright © 2006 - Net Industries, worldwide.
Do not copy, download, transfer, or otherwise replicate the site content in whole or in part.

Links to articles and home page are always encouraged.

[back]
ERYTHRAE [mod. Litri] 		[next]
ERZERUM, or ARZRUM (Arm. Garin)

Site © 2006 - Net Industries