Geodesic
La struttura cristallina della kernite, Na2B4O6(OH)2·3 H2O
Atti della Accademia nazionale dei Lincei. Rendiconti della Classe di scienze fisiche, matematiche e naturali, Série 8, Tome 42 (1967) no. 2, pp. 236-251 
Cialdi, Gloria; Corazza, Egizio; Sabelli, Cesare. La struttura cristallina della kernite, Na2B4O6(OH)2·3 H2O. Atti della Accademia nazionale dei Lincei. Rendiconti della Classe di scienze fisiche, matematiche e naturali, Série 8, Tome 42 (1967) no. 2, pp. 236-251. http://geodesic.mathdoc.fr/item/RLINA_1967_8_42_2_a16/
@article{RLINA_1967_8_42_2_a16,
     author = {Cialdi, Gloria and Corazza, Egizio and Sabelli, Cesare},
     title = {La struttura cristallina della kernite, {Na2B4O6(OH)2{\textperiodcentered}3} {H2O}},
     journal = {Atti della Accademia nazionale dei Lincei. Rendiconti della Classe di scienze fisiche, matematiche e naturali},
     pages = {236--251},
     year = {1967},
     volume = {Ser. 8, 42},
     number = {2},
     language = {it},
     url = {http://geodesic.mathdoc.fr/item/RLINA_1967_8_42_2_a16/}
}
TY  - JOUR
AU  - Cialdi, Gloria
AU  - Corazza, Egizio
AU  - Sabelli, Cesare
TI  - La struttura cristallina della kernite, Na2B4O6(OH)2·3 H2O
JO  - Atti della Accademia nazionale dei Lincei. Rendiconti della Classe di scienze fisiche, matematiche e naturali
PY  - 1967
SP  - 236
EP  - 251
VL  - 42
IS  - 2
UR  - http://geodesic.mathdoc.fr/item/RLINA_1967_8_42_2_a16/
LA  - it
ID  - RLINA_1967_8_42_2_a16
ER  - 
%0 Journal Article
%A Cialdi, Gloria
%A Corazza, Egizio
%A Sabelli, Cesare
%T La struttura cristallina della kernite, Na2B4O6(OH)2·3 H2O
%J Atti della Accademia nazionale dei Lincei. Rendiconti della Classe di scienze fisiche, matematiche e naturali
%D 1967
%P 236-251
%V 42
%N 2
%U http://geodesic.mathdoc.fr/item/RLINA_1967_8_42_2_a16/
%G it
%F RLINA_1967_8_42_2_a16

Voir la notice de l'article provenant de la source Biblioteca Digitale Italiana di Matematica

The crystal structure of kernite, Na2B4O6(OH)2·3 H2O has been determined by means of x-ray diffraction, using the Weissenberg equiinclination technique. The structure was solved from direct methods, giving the signs to 25% of the observed structure factors, and from a three-dimensional Fourier synthesis. Least squares refinement with 951 independent reflections yielded a reliability index of 0.083, based on the observed reflections only. The approximate positions of the hydrogen atoms could be deduced from stereochemical considerations. The monoclinic cell has dimensions, a = 7.022, b = 9.151, c = 15.676 Å; ß = 108.8°. The space group is P 21/c. For a cell containing four units of Na2B4O6(OH)2·3 H2O, the calculated density is 1.904 g·cm-3. The atoms within the square brackets are interconnected along the y axis so as to form an infinite chain complex [B4O6(OH)2]n-2n. Both sodium atoms coordinate five oxygens according to a distorted trigonal bipyramid. The Na(1) and Na(2) coordination polyhedra are connected by a corner, and Na(1) shares an edge with its centro-symmetrical one, to form a four-membered group. The boron-oxygen chains, two per cell, are linked three-dimensionally by the Na polyhedra groups and by hydrogen bonds.

[1] J. Garrido, Symmetrie und raumgruppe des Kernits (Na2B4O7·4 H2O), «Zeit, für Krist.», LXXXII, 468 (1932).

[2] W. Minder, Über den Bau einiger Hydrate von Natriumdiborat, «Zeit, für Krist.», XCII, 301 (1935).

[3] J. L. Amoros, Nota sobre la macla (011) de la Kernita, «Estudios Geològicos», VII, 21 (1947).

[4] G. L. Christ e M. N. Garrels, Relations among sodium Borate hydrates at the Kramer deposit, Boron, California, «Am. Jour. Sci.», 257, 516 (1959).

[5] P. J. Bray, J. O. Edwards, J. G. O'Keefe, V. F. Ross e I. Tatsuzaki, Nuclear magnetic resonance studies of B11 in crystalline borates, «Jour. Chem. Phys.», 35, 435 (1961).

[6] H. E. Petch, K. S. Pennington e J. D. Cuthbert, On Christ's postulated boron-oxygen polyions in some hydrated borates of unknown crystal structures, «Am. Min.», 47, 401 (1962).

[7] V. Ross e J. O. Edwards, On the crystal structure of kernite, Na2B4O7·4 H2O, «Acta Cryst.», 12, 258 (1959).

[8] M. M. Woolfson, Direct methods in crystallography, Clarendon Press, Oxford (1961). | MR | Zbl

[9] D. D. Cromer e J. T. Waber, Scattering factors computed from relativistic Dirac-Slater wave functions, «Acta Cryst.», 18, 104 (1965).

[10] International Tables for x-ray crystallography, Vol. III, Kynoch Press, Birmingham (1962).

[11] V. Albano, P. L. Bellon, F. Pompa e V. Scatturin, Programmi cristallografici per l'elaboratore I.B.M. 1620. Nota IV: Affinamento di una struttura cristallina col metodo dei minimi quadrati, «Ric. Sci.», 3 A, 1067 (1963).

[12] D. W. I. Cruikshank, D. E. Pilling, A. Bujosa, F. M. Lovell e M. R. Truter, Crystallographic calculations on the Ferranti Pegasus and Mark I computer. In: Computing methods and the phase problem in x-ray crystal analysis, Pergamon Press, London 32 (1961).

[13] C. L. Christ, Crystal chemistry and systematic classification of hydrated borate minerals, «Am. Min.», 45, 334 (1960).

[14] C. Tennyson, Eine systematic der Borate auf Kristallchemischer grundlage, «Fortschr. Miner.», 41, 64 (1963).