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Title: Synthesis and crystal structure of a magnesium--lithium--scandium protopyroxene

Journal Article · · Am. Mineral.; (United States)
OSTI ID:5308635
 [1];
  1. Los Alamos Scientific Lab., NM

Crystals of protopyroxene solid solution, Li/sub x/Sc/sub x/Mg/sub 2-x/Si/sub 2/O/sub 6/, 0.1 equal to or less than x equal to or less than 0.35, were grown, in solvents of the system Li/sub 2/O-V/sub 2/O/sub 5/-MoO/sub 3/, by cooling from 1350 to 650/sup 0/ at 1.5/sup 0/C per hour. The crystals are transparent, euhedral, and prismatic, elongate parallel to c and up to 15 x 4 x 3 mm in size, with well-developed (010), (110), and (121) faces. The cell edges used for structure analysis are: a = 9.251, b = 8.773, and c = 5.377A. Long-exposure x-ray precession photographs showed no diffraction maxima inconsistent with space group Pbcn and no evidence of stack disorder. The crystal structure was refined from 1507 measured x-ray intensities, of which 826 were greater than 3sigma of the background intensity. Refinements of the structure in space groups P2/sub 1/cn, Pb2n, Pbc2/sub 1/, and P2/c yielded structures which did not differ significantly from that in space group Pbcn. The structure is ordered with all of the Sc/sup 3 +/ in M1 and all of the Li/sup +/ in M2.

OSTI ID:
5308635
Journal Information:
Am. Mineral.; (United States), Vol. 62:11/12
Country of Publication:
United States
Language:
English