TY - JOUR

T1 - Shkatulkalite, a rare mineral from the Lovozero Massif, Kola Peninsula

T2 - A re-investigation

AU - Zolotarev, Andrey A.

AU - Selivanova, Ekaterina A.

AU - Krivovichev, Sergey V.

AU - Savchenko, Yevgeny E.

AU - Panikorovskii, Taras L.

AU - Lyalina, Lyudmila M.

AU - Pautov, Leonid A.

AU - Yakovenchuk, Victor N.

PY - 2018/7/18

Y1 - 2018/7/18

N2 - The crystal structure of shkatulkalite has been solved from the crystal from the Lovozero alkaline massif, Kola Peninsula, Russia. The mineral is monoclinic, P2/m, a = 5.4638(19), b = 7.161(3), c = 15.573(6) angstrom, beta= 95.750(9)degrees , V = 606.3(4) angstrom(3), R-1 = 0.080 for 1551 unique observed reflections. The crystal structure is based upon the HOH blocks consisting of one octahedral (O) sheet sandwiched between two heteropolyhedral (H) sheets. The blocks are parallel to the (001) plane and are separated from each other by the interlayer space occupied by Na1 atoms and H2O groups. The Na2, Na3, and Ti sites are located within the O sheet. The general formula of shkatulkalite can be written as Na-5(Nb1-xTix)(2)(Ti(1-y)Mn(2+)y)[Si2O7](2)O-2(OH)(2).nH(2)O, where x + y = 0.5 and x approximate to y approximate to 0.25 for the sample studied. Shkatulkalite belongs to the seidozerite supergroup and is a member of the lamprophyllite group. The species most closely related to shkatulkalite are vuonnemite and epistolite. The close structural relations and the reported observations of pseudomorphs of shkatulkalite after vuonnemite suggest that, at least in some environments, shkatulkalite may form as a transformation mineral species.

AB - The crystal structure of shkatulkalite has been solved from the crystal from the Lovozero alkaline massif, Kola Peninsula, Russia. The mineral is monoclinic, P2/m, a = 5.4638(19), b = 7.161(3), c = 15.573(6) angstrom, beta= 95.750(9)degrees , V = 606.3(4) angstrom(3), R-1 = 0.080 for 1551 unique observed reflections. The crystal structure is based upon the HOH blocks consisting of one octahedral (O) sheet sandwiched between two heteropolyhedral (H) sheets. The blocks are parallel to the (001) plane and are separated from each other by the interlayer space occupied by Na1 atoms and H2O groups. The Na2, Na3, and Ti sites are located within the O sheet. The general formula of shkatulkalite can be written as Na-5(Nb1-xTix)(2)(Ti(1-y)Mn(2+)y)[Si2O7](2)O-2(OH)(2).nH(2)O, where x + y = 0.5 and x approximate to y approximate to 0.25 for the sample studied. Shkatulkalite belongs to the seidozerite supergroup and is a member of the lamprophyllite group. The species most closely related to shkatulkalite are vuonnemite and epistolite. The close structural relations and the reported observations of pseudomorphs of shkatulkalite after vuonnemite suggest that, at least in some environments, shkatulkalite may form as a transformation mineral species.

KW - CRYSTAL-CHEMISTRY

KW - EPISTOLITE

KW - EXCHANGE

KW - Kola Peninsula

KW - Lovozero alkaline massif

KW - RUSSIA

KW - STRUCTURE TOPOLOGY

KW - SUPERGROUP

KW - TITANIUM DISILICATE MINERALS

KW - TITANOSILICATES

KW - TS-BLOCK MINERALS

KW - crystal structure

KW - niobium

KW - shkatulkalite

KW - titanium

KW - titanosilicate

KW - transformation mineral species

KW - vuonnemite

UR - http://www.scopus.com/inward/record.url?scp=85050655345&partnerID=8YFLogxK

U2 - 10.3390/min8070303

DO - 10.3390/min8070303

M3 - Article

AN - SCOPUS:85050655345

VL - 8

SP - 303

JO - Minerals

JF - Minerals

SN - 2075-163X

IS - 7

M1 - 303

ER -