From structure topology to chemical composition. XXVIII. Titanium silicates: Jinshajiangite from the Oktyabr'skii massif, Donetsk region, Ukraine, a new occurrence

Here we report electron-microprobe data and unit-cell parameters for jinshajiangite, ideally NaBaFe^2þ ₄Ti₂(Si₂O₇)₂ O₂(OH)₂F, from a new locality: the Oktyabr'skii massif in the coastal area of the Azov Sea, Donetsk region, Ukraine. Chemical analysis by electron microprobe gave Nb₂O₅ 1.59, ZrO₂ 0.61, TiO₂ 17.07, SiO₂ 27.60, Al₂O₃ 0.08, Fe₂O₃ 2.04, FeO 16.42, BaO 9.81, ZnO 0.76, MnO 12.97, CaO 1.82, MgO 0.07, K₂O 2.05, Na₂O 2.51, F 2.48, H₂O 1.92, O ¼ F -1.04, sum 98.76 wt.%; H₂O was determined in accord with the required number of monovalent anions for the Ti-dominant perraultite-type minerals: OH þ F ¼ 3 pfu; the Fe^3þ/Fe^2þ ratio was assigned in accord with Mössbauer-spectroscopy results for jinshajiangite from a different locality. The empirical formula calculated on the basis of 19 (O þ F) is (Na_0.71Ca_0.28 A_0.01)_R1(Ba_0.56K_0.38A_0.06)_R1(Fe^2þ _1.99Mn_1.59Fe^3þ _0.22Zn_0.08Mg_0.02Al_0.01A_0.09)_R4 (Ti_1.86Nb_0.10Zr_0.04)_R2(Si_4.00O₁₄)O₂ [(OH)_1.86F_0.14]_R2F_1.00, Z ¼ 4. Unit-cell parameters from the single-crystal data were determined by least-squares refinement of 9807 reflections with I. 10rI and are as follows: a ¼ 10.726(8), b ¼ 13.834(10), c ¼ 11.065(8) Å, a ¼ 108.172(5), b ¼ 99.251(7), c ¼ 90.00(1)8, V ¼ 1537.5(3.4) ų, space group C-1.