Hoelite

Hoelit ( chemically anthraquinone ) is a rarely occurring mineral from the mineral class of organic compounds. It crystallizes in the monoclinic crystal system with the chemical composition ( C6H4 ) 2 ( CO) 2 and develops fine aristocratic, partly pseudo - orthorhombic crystals in the millimeter range of yellow to yellow-green color.

Etymology and history

The mineral was discovered in 1922 by Adolf Hoel, after which it was named, in pyramids on Spitsbergen.

Classification

In the old classification of minerals according to Strunz ( 8th edition ) of the Hoelit belongs to the Department of nitrogen-free hydrocarbons. Since the Strunz'schen mineral systematics edition ( 9th Edition ) by Strunz is the class of organic minerals, however, is divided differently and the mineral is now in the subsection " 10.CA. " the Department " Various organic minerals ".

The classification of minerals according to Dana sorted the Hoelit in the department of " salts of organic acids with various formulas " one.

Education and Locations

Hoelit forms in burning coal deposits, often together with ammonium chloride and / or sulfur.

The mineral has been found so far except at its type locality Spitsbergen only at Libušín and Radvanice v Čechách ( Okres Trutnov ) in Bohemia (Czech Republic ); and Saxony ( Freital ) in Germany.

Crystal structure

Hoelit crystallizes in the monoclinic crystal system, space group P21 / a with lattice parameters a = 15.810 Å, b = 3.942 Å, c = 7.895 Å and β = 102.72 ° and two formula units per unit cell. The crystal structure consists of individual anthraquinone molecules, which are held together by van der Waals interactions.