Boromuscovite from a granitic pegmatite at Recice, Czech Republic, occurs only as very fine-grained aggregates, and is a mixture of 2M(1) and 1M polytypes. Crystal structures of both polytypes have been simultaneously refined in space groups C2/c and C2/m, respectively, using a coupled Rietveld - static-structure energy-minimization method. Intensity data were collected on a high-resolution powder diffractometer in transmission geometry, with the sample prepared such that preferred orientation is largely avoided. The refinement converged to R(wp) = 13.8% (R(exp) = = 7.9%), R(BRG) (2M(1)) = 3.8%, and R(BRG) (1M) = 3.8%. Boron is evenly distributed between the two polytypes, and <T-O> distances correspond well with the B-content at the corresponding T-sites.

CRYSTAL-STRUCTURE REFINEMENT OF BOROMUSCOVITE POLYTYPES USING A COUPLED RIETVELD STATIC-STRUCTURE ENERGY-MINIMIZATION METHOD

OTTOLINI L
1995

Abstract

Boromuscovite from a granitic pegmatite at Recice, Czech Republic, occurs only as very fine-grained aggregates, and is a mixture of 2M(1) and 1M polytypes. Crystal structures of both polytypes have been simultaneously refined in space groups C2/c and C2/m, respectively, using a coupled Rietveld - static-structure energy-minimization method. Intensity data were collected on a high-resolution powder diffractometer in transmission geometry, with the sample prepared such that preferred orientation is largely avoided. The refinement converged to R(wp) = 13.8% (R(exp) = = 7.9%), R(BRG) (2M(1)) = 3.8%, and R(BRG) (1M) = 3.8%. Boron is evenly distributed between the two polytypes, and distances correspond well with the B-content at the corresponding T-sites.
1995
Istituto di Geoscienze e Georisorse - IGG - Sede Pisa
BOROMUSCOVITE; RIETVELD STRUCTURE; REFINEMENT; CHEMICAL ANALYSIS; POLYTYPE; ENERGY MINIMIZATION
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.14243/240463
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? 15
social impact