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SUMMARY:The high-pressure diffraction studies of potassium and complex car
 bonates: structural trends and stability
DTSTART;VALUE=DATE-TIME:20160706T094000Z
DTEND;VALUE=DATE-TIME:20160706T100000Z
DTSTAMP;VALUE=DATE-TIME:20260811T203040Z
UID:indico-contribution-1189@indico.inp.nsk.su
DESCRIPTION:Speakers: Sergey Rashchenko (Institute of geology and mineralo
 gy SD RAS)\nThe interest to carbonates is determined by their obvious prac
 tical importance\, as well as their abundance in the Earth’s interior an
 d a key role in magma generation\, plume upwelling and diamond growth [1].
  Despite the structural trend of the high-temperature phases of all alkali
 ne carbonates is well understood [2]\, almost nothing is known about high-
 pressure behavior of these compounds. In this work we use a combination of
  the high-pressure diffraction experiments in diamond anvil cell (4th beam
 line of the VEPP-3 storage ring of the SSTRC\, Novosibirsk) and ab-initio 
 calculations to determine the crystal structure of the high-pressure phase
  of K2CO3 at 3.1 GPa. \nAmong the structures founded in our calculations\,
  the Р21/с-structure shows relevant matching with the experimental patte
 rn (Fig. 1). The comparison with the experimental data on Li2CO3 allows to
  reconstruct the common structural trend\, which is consistent with the si
 mple rule that the structure of the high-pressure polymorph is the same as
  the ambient structure of a heavier element compound from the same group o
 f the periodic table.\nWe also report on the compressibility and structure
  behaviour of thaumasite Ca3Si(OH)6(CO3)(SO4)•12Н2О\, a unique known m
 ineral that possesses Si coordinated by six hydroxyl groups and stable at 
 ambient P/Tconditions [3]. Our data show a strong dependence of its high-p
 ressure stability limit on the nature of compressing medium.\nThis work is
  supported by the Russian Foundation for Basic Research (grant No 15-55-45
 070) and the Ministry of Education and Science of Russian Federation (# 14
 .B25.31.0032).\n\nReferences\n[1] Litasov K.D. (2011) Russian Geology and 
 Geophysics 52\, 475-492.\n[2] Swainson I.P. et al. (1995) J. Phys.-Condens
 . Mat. 7\, 4395-4417.\n[3] Gatta G.D. et al.(2012) American Mineralogist\,
  97\,1060-1069.\n\nhttps://indico.inp.nsk.su/event/3/contributions/1189/
LOCATION:Budker INP Conference Hall
URL:https://indico.inp.nsk.su/event/3/contributions/1189/
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