The key cation-sites M3 and A1 (and, in principle, M2) determine the root name. In both clinozoisite and allanite subgroups no prefix is added to the root name if M1 = Al. The prefixes ferri, mangani, chromo, and vanado indicate dominant Fe 3+ , Mn 3+ , Cr 3+ , and V 3+ on M1, respectively. In the dollaseite subgroup no prefix is added to the root name if M1 = Mg. Otherwise a proper prefix must be attached; the prefixes ferro and mangano indicate dominant Fe 2+ and Mn 2+ at M1, respectively. The dominant cation on A2 (other than Ca) is treated according to the Extended Levinson suffix designation. This simple nomenclature requires renaming of the following approved species: Niigataite (old) = clinozoisite-(Sr) (new), hancockite (old) = epidote-(Pb) (new), tweddillite (old) = manganipiemontite-(Sr) (new). Minor modifications are necessary for the following species: Strontiopiemontite (old) = piemontite-(Sr) (new), androsite-(La) (old) = manganiandrosite-(La) (new). Before a mineral name can be assigned, the proper subgroup has to be determined. The determination of a proper subgroup is made by the dominating valence at M3, M1, and A2 expressed as M 2+ and or M 3+ , not by a single, dominant ion (i.e., Fe 2+ , or Mg, or Al). In addition, the dominant valence on O4: X -or X 2-must be ascertained. The dominant trivalent cation on M3 determines the name, whereas the A2 cation appearing in the suffix has to be selected from among the divalent cations. (2) Allanite and dollaseite subgroups: For the sites involved in the charge compensation of a heterovalent substitution in A2 and O4 (i.e. M3 in the allanite subgroup; M3 and M1 in the dollaseite subgroup), identification of the relevant end-member formula must take into account the dominant divalent charge-compensating octahedral cation (M 2+ ) and not the dominant cation in these sites.Formal guidelines and examples are provided in order to determine a mineral "working name" from electron-microprobe analytical data.

Garnet: A Fast Lithium-IonConductor. -Single crystals of the title compound are prepared by sintering mixtures of ZrO2, La2O3, and Li2CO3 using ceramic crucibles in initial steps and later sealed Pt capsules. The samples contain small amounts of Al, probably originating from the crucibles. Li7La3Zr2O12 crystallizes in the cubic space group Ia3d with Z = 8 (single crystal XRD) between 100 and 500 K. Li atoms are located on at least two structural sites that are partially occupied, while other Li atoms in the structure appear to be delocalized. Li NMR spectroscopy indicates fast Li ion diffusion at room temperature. Using solely Pt crucibles during sintering a tetragonal Li7La3Zr2O12 room temp. phase (powder XRD) is obtained which undergoes a phase transition to a cubic phase between 100 and 150°C. Cubic "Li 7 La 3 Zr 2 O 12 " may be stabilized at ambient conditions relative to its slightly less conducting tetragonal modification via small amounts of Al 3+ . A simple crystal chemical model is proposed to explain why cubic Al-containing Li 7 La 3 Zr 2 O 12 is (meta)stable at ambient conditions, and why it is such a good ion conductor. -(GEIGER*, C. A.; ALEKSEEV, E.; LAZIC, B.; FISCH, M.; ARMBRUSTER, T.; LANGNER, R.; FECHTELKORD, M.; KIM, N.; PETTKE, T.; WEPPNER, W.; Inorg. Chem. 50 (2011) 3, 1089-1097, http://dx.

This report embodies recommendations on zeolite nomenclature approved by the International Mineralogical Association, Commission on New Minerals and Mineral Names. In a working definition of a zeolite mineral used for this review, structures containing an interrupted framework of tetrahedra are accepted where other zeolitic properties prevail, and complete substitution by elements other than Si and Al is allowed. Separate species are recognized in topologically distinctive compositional series in which different extra-framework cations are the most abundant in atomic proportions. To name these, the appropriate chemical symbol is attached by a hyphen to the series name as a suffix, except for the names harmotome, pollucite and wairakite in the phillipsite and analcime series. Differences in space-group symmetry and in order-disorder relationships in zeolites having the same topologically distinctive framework do not in general provide adequate grounds for recognition of separate species. Zeolite species are not to be distinguished solely on the ratio Si : Al except for heulandite (Si : Al < 4.0) and clinoptilolite (Si : Al ≥ 4.0). Dehydration, partial hydration, and overhydration are not sufficient grounds for the recognition of separate species of zeolites. Use of the term "ideal formula" should be avoided in referring to a simplified or averaged formula of a zeolite. Newly recognized species in compositional series are as follows: brewsterite-Sr, -Ba, chabazite-Ca, -Na, -K, clinoptilolite-K, -Na, -Ca, dachiardite-Ca, -Na, erionite-Na, -K, -Ca, faujasite-Na, -Ca, -Mg, ferrierite-Mg, -K, -Na, gmelinite-Na, -Ca, -K, heulandite-Ca, -Na, -K, -Sr, levyne-Ca, -Na, paulingite-K, -Ca, phillipsite-Na, -Ca, -K, and stilbite-Ca, -Na. Key references, type locality, origin of name, chemical data, IZA structure-type symbols, space-group symmetry, unit-cell dimensions, and comments on structure are listed for 13 compositional series, 82 accepted zeolite mineral species, and three of doubtful status. Herschelite, leonhardite, svetlozarite, and wellsite are discredited as mineral species names. Obsolete and discredited names are listed.Keywords: zeolite nomenclature, herschelite, leonhardite, svetlozarite, wellsite, brewsterite, chabazite, clinoptilolite, dachiardite, erionite, faujasite, ferrierite, gmelinite, heulandite, levyne, paulingite, phillipsite, stilbite. SOMMAIRECe rapport contient les recommandations à propos de la nomenclature des zéolites, telles qu'approuvées par l'Association minéralogique internationale, commission des nouveaux minéraux et des noms de minéraux. Dans la définition d'une zéolite retenue ici, les structures contenant une trame interrompue de tétraèdres sont acceptées dans les cas où les autres propriétés satisfont les critères de cette famille de minéraux. De plus, il peut y avoir remplacement complet de Si et Al par d'autres éléments. Des espèces distinctes font partie de séries de compositions dont l'agencement topologique est le même, le cation dominant ne faisant pas partie de la trame ...

This report embodies recommendations on zeolite nomenclature approved by the International Mineralogical Association Commission on New Minerals and Mineral Names. In a working definition of a zeolite mineral used for this review, interrupted tetrahedral framework structures are accepted where other zeolitic properties prevail, and complete substitution by elements other than Si and Al is allowed. Separate species are recognized in topologically distinctive compositional series in which different extra-framework cations are the most abundant in atomic proportions. To name these, the appropriate chemical symbol is attached by a hyphen to the series name as a suffix except for the names harmotome, pollucite and wairakite in the phillipsite and analcime series. Differences in space-group symmetry and in order-disorder relationships in zeolites having the same topologically distinctive framework do not in general provide adequate grounds for recognition of separate species. Zeolite species are not to be distinguished solely on Si : Al ratio except for the heulandite (Si : Al < 4.0) and clinoptilolite (Si : Al ≥ 4.0) series. Dehydration, partial hydration, and over-hydration are not sufficient grounds for the recognition of separate species of zeolites. Use of the term "ideal formula" should be avoided in referring to a simplified or averaged formula of a zeolite. Newly recognized species in compositional series are as follows:

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