Incommensurately modulated twin structure of nyerereite

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Marco E. Ciriotti
Messaggi: 23140
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
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Incommensurately modulated twin structure of nyerereite

Messaggio da Marco E. Ciriotti » mer 22 feb, 2017 8:53

Prossima pubblicazione.

Referenza:
▪ Bolotina, N.B., Gavryushkin, P.N., Korsakov, A.V., Rashchenko, S.V., Seryotkin, Yu.,V., Golovin, A.V., Moine, B.N., Zaitsev, A.N., Litasov, K.D. (2017): Incommensurately modulated twin structure of nyerereite Na1.64K0.36Ca(CO3)2. Acta Crystallographica, B73, (in press).

Synopsis:
The incommensurately modulated twin structure of nyerereite Na0.82K0.18·2Ca(CO3)2 has been first determined and then compared with the modulated structure of γ-Na2CO3.
Marco E. Ciriotti

«Things are interesting only in so far as they relate themselves to other things»

Avatar utente
Marco E. Ciriotti
Messaggi: 23140
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
Contatta:

Re: Incommensurately modulated twin structure of nyerereite

Messaggio da Marco E. Ciriotti » lun 03 apr, 2017 12:45

Pubblicazione effettuata.

Referenza:
▪ Bolotina, N.B., Gavryushkin, P.N., Korsakov, A.V., Rashchenko, S.V., Seryotkin, Yu.,V., Golovin, A.V., Moine, B.N., Zaitsev, A.N., Litasov, K.D. (2017): Incommensurately modulated twin structure of nyerereite Na1.64K0.36Ca(CO3)2. Acta Crystallographica, B73, 276-284.

Abstract:
he incommensurately modulated twin structure of nyerereite Na1.64K0.36Ca(CO3)2 has been first determined in the (3 + 1)-dimensional symmetry group Cmcm(α00)00s with modulation vector q = 0.383a*. Unit-cell values are a = 5.062 (1), b = 8.790 (1), c = 12.744 (1) Å. Three orthorhombic components are related by threefold rotation about [001]. Discontinuous crenel functions are used to describe the occupation modulation of Ca and some CO3 groups. The strong displacive modulation of the O atoms in vertexes of such CO3 groups is described using x-harmonics in crenel intervals. The Na, K atoms occupy mixed sites whose occupation modulation is described in two ways using either complementary harmonic functions or crenels. The nyerereite structure has been compared both with the commensurately modulated structure of K-free Na2Ca(CO3)2 and with the widely known incommensurately modulated structure of γ-Na2CO3.
Marco E. Ciriotti

«Things are interesting only in so far as they relate themselves to other things»

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