Preservation of samarskite structure in a metamict ABO4
mineral: a key to crystal structure identification

J 2010

Preservation of samarskite structure in a metamict ABO4 mineral: a key to crystal structure identification

TOMAŠIĆ, Nenad; Andreja GAJOVIĆ; Vladimir BERMANEC; Maša Rajić LINARIĆ; Dang Sheng SU et al.

Základní údaje

Originální název

Preservation of samarskite structure in a metamict ABO4 mineral: a key to crystal structure identification

Autoři

TOMAŠIĆ, Nenad; Andreja GAJOVIĆ; Vladimir BERMANEC; Maša Rajić LINARIĆ; Dang Sheng SU a Radek ŠKODA

Vydání

European Journal of Mineralogy, 2010, 0935-1221

Další údaje

Jazyk

angličtina

Typ výsledku

Článek v odborném periodiku

Obor

10500 1.5. Earth and related environmental sciences

Stát vydavatele

Německo

Utajení

není předmětem státního či obchodního tajemství

Impakt faktor

Impact factor: 1.469

Označené pro přenos do RIV

Ano

Kód RIV

RIV/00216224:14310/10:00040601

Organizační jednotka

Přírodovědecká fakulta

UT WoS

000278166000010

Klíčová slova anglicky

samarskite; low-temperature modification; metamictisation; pre-metamict structure

Příznaky

Mezinárodní význam, Recenzováno

Změněno: 7. 11. 2010 13:32, doc. Mgr. Radek Škoda, Ph.D.

Anotace

V originále

Relics of the original samarskite structure were identified in a metamict ABO4 mineral from Beinmyr pegmatite, Norway, using selected area electron diffraction (SAED) and high-resolution transmission electron microscopy (HRTEM). The chemical composition of the sample confirmed the affiliation to the samarskite group giving general formula (REE0.322Ca0.269Fe0.231U0.142Mn0.031Pb0.011Th0.010Zr0.010Al0.004Sc0.002Na0.001K0.001)1.034(Nb0.707Ta0.267Ti0.069W0.017Sn0.007)1.067O4 which corresponds well to the general ABO4 stoichiometry of the samarskite group. The structure identified by transmission electron microscopy (TEM) techniques is well related to the proposed low-temperature samarskite modification (Sugitani et al. 1985) crystallizing in Pbcn space group with the cell parameters a=5.69(2) A, b=4.91(2) A, c=5.21(2) A. The original mineral sample showed to be X-ray amorphous. Gradual recrystallisation in air in the temperature range between 400 and 1000oC yielded a pyrochlore phase being stable at all experimental temperatures. At 800oC a high-temperature samarskite phase (s.g. P2/c) co-crystallised with an increase in crystallinity at 1000oC. Recrystallisation in a reducing atmosphere (Ar/H2) did not yield the high-temperature samarskite phase solely. Unsuccessful recrystallisation of the high-temperature samarskite modification is mainly related to an alteration which shifted the composition of samarskite to pyrochlore as evidenced by occurrence of altered domains in the sample. Raman spectra of thermally untreated samarskite showed generally metamict nature of the mineral, although a few normal Nb-O vibration modes can be resolved indicating BO6 arrangement similar to the one of columbite.

Návaznosti

KJB301630801, projekt VaV

Název: Interakce metamiktních minerálů s hydrotermálnímy fluidy a její význam geologickém prostředí

Investor: Akademie věd ČR, Interakce metamiktních minerálů s hydrotermálnímy fluidy a její význam geologickém prostředí

Citovat

TOMAŠIĆ, Nenad; Andreja GAJOVIĆ; Vladimir BERMANEC; Maša Rajić LINARIĆ; Dang Sheng SU a Radek ŠKODA. Preservation of samarskite structure in a metamict ABO4 mineral: a key to crystal structure identification. European Journal of Mineralogy. 2010, roč. 22, č. 3, s. 435-442. ISSN 0935-1221.

@article{902348,
   author = {Tomašić, Nenad and Gajović, Andreja and Bermanec, Vladimir and Linarić, Maša Rajić and Su, Dang Sheng and Škoda, Radek},
   article_number = {3},
   keywords = {samarskite; low-temperature modification; metamictisation; pre-metamict structure},
   language = {eng},
   issn = {0935-1221},
   journal = {European Journal of Mineralogy},
   title = {Preservation of samarskite structure in a metamict ABO4 mineral: a key to crystal structure identification},
   volume = {22},
   year = {2010}
}

TY  - JOUR
ID  - 902348
AU  - Tomašić, Nenad - Gajović, Andreja - Bermanec, Vladimir - Linarić, Maša Rajić - Su, Dang Sheng - Škoda, Radek
PY  - 2010
TI  - Preservation of samarskite structure in a metamict ABO4 mineral: a key to crystal structure identification
JF  - European Journal of Mineralogy
VL  - 22
IS  - 3
SP  - 435-442
EP  - 435-442
SN  - 09351221
KW  - samarskite
KW  - low-temperature modification
KW  - metamictisation
KW  - pre-metamict structure
N2  - Relics of the original samarskite structure were identified in a metamict ABO4 mineral from Beinmyr pegmatite, Norway, using selected area electron diffraction (SAED) and high-resolution transmission electron microscopy (HRTEM). The chemical composition of the sample confirmed the affiliation to the samarskite group giving general formula (REE0.322Ca0.269Fe0.231U0.142Mn0.031Pb0.011Th0.010Zr0.010Al0.004Sc0.002Na0.001K0.001)1.034(Nb0.707Ta0.267Ti0.069W0.017Sn0.007)1.067O4 which corresponds well to the general ABO4 stoichiometry of the samarskite group. The structure identified by transmission electron microscopy (TEM) techniques is well related to the proposed low-temperature samarskite modification (Sugitani et al. 1985) crystallizing in Pbcn space group with the cell parameters a=5.69(2) A, b=4.91(2) A, c=5.21(2) A. The original mineral sample showed to be X-ray amorphous. Gradual recrystallisation in air in the temperature range between 400 and 1000oC yielded a pyrochlore phase being stable at all experimental temperatures. At 800oC a high-temperature samarskite phase (s.g. P2/c) co-crystallised with an increase in crystallinity at 1000oC. Recrystallisation in a reducing atmosphere (Ar/H2) did not yield the high-temperature samarskite phase solely. Unsuccessful recrystallisation of the high-temperature samarskite modification is mainly related to an alteration which shifted the composition of samarskite to pyrochlore as evidenced by occurrence of altered domains in the sample. Raman spectra of thermally untreated samarskite showed generally metamict nature of the mineral, although a few normal Nb-O vibration modes can be resolved indicating BO6 arrangement similar to the one of columbite.
ER  -

TOMAŠI$\backslash$'C, Nenad; Andreja GAJOVI$\backslash$'C; Vladimir BERMANEC; Maša Raji$\backslash$'c LINARI$\backslash$'C; Dang Sheng SU a Radek ŠKODA. Preservation of samarskite structure in a metamict ABO4 mineral: a key to crystal structure identification. \textit{European Journal of Mineralogy}. 2010, roč.~22, č.~3, s.~435-442. ISSN~0935-1221.

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