| Библ. ссылка: | Galuskin E.V., Gfeller F., Galuskina I.O., Armbruster T., Bailau R., Sharygin V.V. Mayenite supergroup, part I: Recommended nomenclature // European Journal of Mineralogy. - 2015. - Vol.27. - Iss. 1. - P.99-111. - ISSN 0935-1221. - EISSN 1617-4011. |
| Реферат: | eng: The mayenite supergroup, accepted by the IMA-CNMNC (proposal 13-C), is a new mineral supergroup comprising two groups of minerals isostructural with mayenite (space group No. 220, I (4) over bar 3d, a approximate to 12 angstrom) with the general formula X12T14O32-x(OH)(3x)[W6-3x]: the mayenite group (oxides) and the wadalite group (silicates), for which the anionic charge over 6 W sites is -2 and -6, respectively. Currently only minerals dominated by end-members with x = 0 and the simplified formula X12T14O32[W-6] have been reported. The mayenite group includes four minerals: (1) chlormayenite, Ca12Al14O32[square Cl-4(2)]; (2) chlorkyuygenite, Ca12Al14O32[(H2O)(4)Cl-2]; (3) fluormayenite, Ca12Al14O32[square F-4(2)]; and (4) fluorkyuygenite, Ca12Al14O32[(H2O)(4) F-2]. The wadalite group comprises the two mineral species wadalite, with the end-member formula Ca12Al10Si4O32[Cl-6], and eltyubyuite, with the end-member formula Ca12Fe103+Si4O32[Cl-6]. Current research on minerals and synthetic compounds indicates that minerals close to the composition of ideal end-members, such as Ca12Fe103+ Si4O32[F-6], Ca12Si9Mg5O32[Cl-6] and Ca12Al14O30(OH)(6)[square(6)], could be found in Nature. A detailed re-examination of the type specimens of mayenite, originally described as Ca12Al14O33, indicates that Ca12Al14O32[square Cl-4(2)], 1 is its correct end-member formula. Consequently, we are redefining and renaming mayenite as chlormayenite, Ca12Al14O32[square Cl-4(2)], whereas the name mayenite would be reserved for a potential mineral with the end-member composition Ca12Al14O32[square O-5]. As a consequence, the mineral brearleyite, Ca12Al14O32[square Cl-4(2]), described in 2011 is identical with chlormayenite and is therefore discredited. By analogy with chlormayenite we changed the name of kyuygenite into chlorkyuygenite.
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