A.P. Khomyakov

Crystal structure of a new Mn, Na-ordered analogue of eudialyte with the symmetry R3

The crystal structure of a new representative of the eudialyte family was studied. This mineral is characterized by a low calcium content and by ordering the elements that isomorphically replace calcium, which lowers the symmetry from R3m to R3. The structure of the sample under study consists of the six-membered rings with two octahedra of substantially different volumes, one occupied mainly by manganese and the other, mainly by sodium and characterized by the average distances of 2.22 and 2.45 Å, respectively. The formation of such octahedra is the most characteristic structural feature of the third low-symmetry mineral of the eudialyte family.

Refined crystal structure of iron-rich triclinic astrophyllite

AbstractCrystal structure of Fe-rich triclinic astrophyllite K2NaFe7 [Ti2Si8O26F](OH)4 is refined (a Syntex Pn

Refinement of the crystal structure of sanidine-like feldspar

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Crystal structure of sobolevite

n automatic diffractometer, 3809 reflections, 2θ/θ scan, R = 0.041): a = 5.365(2), b = 11.88(1), c = 21.03(2) Å, α = 84.87(6)°, β = 92.25(5)°, γ = 103.01(4)°, sp. gr. An

Crystal structure of tetranatrolite

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Crystal structure of natural hydroxyl-containing cancrinite

n, Z = 2, dcalcd = 3.29 g/cm3. The refined structure is identical to that reported earlier. The structure is built by three-layer TOT sheets in which an O layer of Fe-octahedra is sandwiched between the T layers consisting of Si-tetrahedra and Ti-octahedra. It is established that differently chosen unit cells of the mineral are interrelated.