The seidozerite supergroup of TS-block minerals : nomenclature and classification, with change of the following names : rinkite to rinkite-(Ce), mosandrite to mosandrite-(Ce), hainite to hainite-(Y) and innelite-1T to innelite-1A
Articolo
Data di Pubblicazione:
2017
Citazione:
The seidozerite supergroup of TS-block minerals : nomenclature and classification, with change of the following names : rinkite to rinkite-(Ce), mosandrite to mosandrite-(Ce), hainite to hainite-(Y) and innelite-1T to innelite-1A / E. Sokolova, F. Cámara. - In: MINERALOGICAL MAGAZINE. - ISSN 0026-461X. - 81:6(2017 Dec), pp. 1457-1484. [10.1180/minmag.2017.081.010]
Abstract:
Here we report a nomenclature and classification for the seidozerite-supergroup minerals. The TS (Titanium-Silicate) block is the main structural unit in all seidozerite-supergroup structures; it consists of a central O (O = Octahedral) sheet and two adjacent H (H = Heteropolyhedral) sheets where Si2O7 groups occur in the H sheets. The TS block is characterized by a planar minimal cell based on translation vectors, t1 and t2, the lengths of these vectors are t1 ≈ 5.5 and t2 ≈ 7 A, and t1 ^ t2 is close to 90°. The forty-five minerals of the sedozerite supergroup are divided into four groups based on the content of Ti and topology and stereochemistry of the TS block: in rinkite, bafertisite, lamprophyllite and murmanite groups, Ti (+ Nb + Zr + Fe3+ +Mg + Mn) = 1, 2, 3 and 4 apfu (atoms per formula unit), respectively. All TS-block structures consist either solely of TS blocks or of two types of block: the TS block and an I (Intermediate) block that comprises atoms between two TS blocks. Usually, the I block consists of alkali and alkaline-earth cations, H2O groups and oxyanions (PO4)3-, (SO4)2- and (CO3)2-.The general formula of the TS block is as follows AP 2 BP 2 MH 2 MO 4 (Si2O7)2X4+n, where MH 2 and MO 4 = cations of the H and O sheets; MH = Ti, Nb, Zr, Y, Mn, Ca + REE, Ca;MO = Ti, Zr, Nb, Fe3+, Fe2+, Mg, Mn, Zn, Ca, Na; AP and BP = cations at the peripheral (P) sites = Na, Ca + REE, Ca, Zn, Ba, Sr, K; X = anions = O, OH, F, H2O; X4+n=XO 4 +XP n , n = 0, 1, 1.5, 2, 4; XP = XP M and XP A = apical anions of MH and AP cations at the periphery of the TS block.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
bafertiste; classification; ideal formula; lamprophyllite and murmanite groups; nomenclature; rinkite; seidozerite supergroup; TS block; geochemistry and petrology
Elenco autori:
E. Sokolova, F. Cámara
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