IMA 2016-088 = rudabányaite

database, nuove specie, discrediti,
ridefinizioni, classificazioni, ecc.
Rispondi
Avatar utente
Marco E. Ciriotti
Messaggi: 25339
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
Contatta:

IMA 2016-088 = rudabányaite

Messaggio da Marco E. Ciriotti » lun 17 dic, 2018 11:47

Prossima pubblicazione.

Referenza:
▪ Effenberger, H., Szakáll, S., Fehér, B., Váczi, T., Zajzon, N. (2019): Rudabányaite, a new mineral with a [Ag2Hg2]4+ cluster cation from the Rudabánya ore deposit (Hungary). European Journal of Mineralogy, 31, (in press).
Marco E. Ciriotti

«Things are interesting only in so far as they relate themselves to other things»

Avatar utente
Marco E. Ciriotti
Messaggi: 25339
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
Contatta:

Re: IMA 2016-088 = rudabányaite

Messaggio da Marco E. Ciriotti » gio 31 gen, 2019 12:28

Prossima pubblicazione.

Referenza:
▪ Effenberger, H., Szakáll, S., Fehér, B., Váczi, T., Zajzon, N. (2019): Rudabányaite, a new mineral with a [Ag2Hg2]4+ cluster cation from the Rudabánya ore deposit (Hungary). European Journal of Mineralogy, 31, (in press).

Abstract:
Rudabányaite was found in cavities of siliceous sphaerosiderite and limonite rocks at the Adolf mine area of the Rudabánya ore deposit (North-East Hungary). The new mineral forms small crystals up to 0.6 mm and aggregates of a few mm across. Usually they have a xenomorphic shape, only occasionally cubic symmetry is morphologically discernible; the crystal forms {110} and {100} were recognized. The crystals are transparent, have yellowish-orange to brownish-yellow colour and a lemon-yellow streak, the lustre is adamantine. The Mohs’ hardness is 3–4. No cleavage was observed. Rudabányaite is optically isotropic. The density could not be measured due to lack of material; ρ(calc.) = 8.04 g/cm3. Electron-microprobe analyses gave the average composition (in wt%) Ag2O 29.39, Hg2O 52.62, As2O5 13.69, Cl 4.62, SO3 0.19, O=Cl −1.04, sum 99.47. The empirical formula based on four oxygen atoms is (Ag2.06Hg2.05)Σ=4.11(As0.97S0.02)Σ=0.99O4Cl1.06; the idealized formula as derived from chemical analyses and crystal-structure investigation is [Ag2Hg2][AsO4]Cl. The crystal-structure investigation was performed on single-crystal X-ray data; the refinements on F2 converged at wR2(F2) = 0.068 and R1(F) = 0.031 for all 972 unique data and 53 variable parameters. Rudabányaite crystallizes in space group F4 ¯ 3c, a = 17.360(3) Å, V = 5231.8 Å3, Z = 32. The crystal structure is characterised by two crystallographically different [M4]4+ cluster cations forming tetrahedra; M = (Ag,Hg) with a ratio Ag:Hg ~ 1:1. There is not any evidence for an order between the Ag and Hg atoms. Small amounts of the M atoms are displaced by ~0.5 Å. Topologically, the barycentres of the [M4]4+ clusters and the As atom positions of the crystal structure of rudabányaite form a cubic primitive lattice with a′ = ½a = 8.68 Å; half of the voids are occupied by Cl atoms.
Marco E. Ciriotti

«Things are interesting only in so far as they relate themselves to other things»

Rispondi

Chi c’è in linea

Visitano il forum: Nessuno e 1 ospite