Island silicates

-

island silicates

Island silicates - a type of silicate.

The main structural motif of the silicate is the tetrahedron with one silicon atom in the center and four oxygen atoms. Tetrahedrons may be singly or in combination with one or more oxygen atoms. Island silicates are the simplest silicates and contain isolated, unrelated silicate tetrahedrons. Their negative charge is neutralized by two- or trivalent metal cations. Combination of tetrahedrons is accomplished by ionic oxygenation bonds. General formula of this silicate: X3Y2 (SiO4) 3, where X and Y are di- and trivalent metal cations.

Minerals belonging to this group are produced at very high temperatures.

The island silicates include minerals such as olivine = peridot, pomegranate, zirconium, sillimanite, andalisite, disten cyanide, topaz, staurolite, willemit or titanite = sfen. Authority control (mineral subclass):

wiki

Comments

Post a Comment

Popular posts from this blog

Association of Jewish handicrafts "Jad Charuzim"

-
The Jewish Handgun Association "Jad Charuzim" - a Jewish craft organization, operating in Galicia since 1875. She was the founder of many synagogues (eg Yad Charuzim Synagogue in Sanok, Jad Charuzim Synagogue in Yaroslav, Zasany Synagogue in Przemysl), burs, self-help and charity activities, libraries, readings and readings. In 1927, in order to enable its members to use small loans, the association established its own credit cooperative "Cooperative Bank of Cooperatives". The Association's activities ceased during World War II. wiki
Read more

Grouping Red Arrows

-
Raggruppamento Frecce Rosse (Red Arrow Group) - Collaborative armed formation of an Italian army composed of Indians, Arabs and Africans during the Second World War. From May to July 1942, an armed formation was formed under the name Raggruppamento Centri Militari, consisting mainly of British Army prisoners of war originating in Arab countries, India and northern and eastern Africa. They were Hindus, Arabs, Sudanese, Tunisians. The officers and the non-commissioned officers were Italian. The formation consisted of three subdivisions: It was about 1.2 thousand. including about 400 Hindus and about 200 Arabs. Colonel Massimo Invrea de Stato headed it. Subsequently, a small number of Tunisians and Indians were sent to Italy to complete their parachute training in Tarquinia. In August 1942, the formation was renamed Raggruppamento Frecce Rosse. After the defeat of the German-Italian forces at El Alamein at the turn of October and November 1942, the Indians and Arabs lost motivation t...
Read more

Stanisław Kryński (translator)

-
Stanisław Kryński (born 20 June 1912 in Warsaw, died 30 January 1967) is a Polish-American philologist, literary critic and translator of English literature. English poets of lakes (William Wordsworth, Samuel Taylor Coleridge and Robert Southey), Robert Burns, Samuel Butler and Edward Gibbon. Graduated from Junior High School. Jan Zamoyski in Warsaw, obtaining a certificate of maturity in 1930. After graduating from the Faculty of Law at the University of Warsaw (1934) he became a master of law; and in 1938 - at the Faculty of Philosophy of the University of Warsaw - also a master of philosophy. At the same time, he also completed a three-year course in French law at the University of Warsaw, obtaining a certificate in 1937 from the Université de Paris. The doctorate of Roman law did not finish because of the outbreak of war. Selected translations wiki
Read more