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21.
L. P. Ogorodova L. V. Mel’chakova M. F. Vigasina L. V. Olysich I. V. Pekov 《Geochemistry International》2009,47(3):260-267
The paper presents the results of a thermochemical and thermal study of cancrinite, (Na6.93Ca0.545K0.01)Σ7.485[(Si6.47Al5.48Fe0.05)Σ12O24](CO3)1.25 · 2.30 H2O, and cancrisilite, (Na7.17 Ca0.01)Σ7.18[(Si7.26Al4.70Fe0.04)Σ12O24][(CO3)1.05(OH)0.21(PO4)0.04(SO4)0.01] · 2.635 H2O, from the Khibina-Lovozero Complex, Kola Peninsula, Russia. Stages of the thermal decomposition of these minerals were studied using IR spectroscopy. The enthalpies of formation of the minerals from elements were determined by melt drop solution calorimetry: Δ f H el 0 (298.15 K) = ?14 490 ± 16 kJ/mol for cancrinite and ?14302 ± 17 kJ/mol for cancrisilite. The values of Δ f H el 0 (298.15 K), S o(298.15 K), and Δ f H el 0 (298.15 K) are determined for cancrinite and cancrisilite of theoretical composition. 相似文献
22.
L. P. Ogorodova L. V. Mel’chakova M. F. Vigasina I. A. Kiseleva I. A. Bryzgalov 《Geochemistry International》2017,55(3):257-262
The thermochemical study of two natural trioctahedral Mg–Fe chlorites—clinochlores was carried out using high-temperature melt solution calorimetry with a Tian–Calvet microcalorimeter. The enthalpies of formation of clinochlores of compositions (Mg4.9Fe 0.3 2+ Al0.8)[Si3.2Al0.8O10](OH)8 (–8811 ± 12 kJ/mol) and (Mg4.3Fe 0.7 2+ Al1.0)[Si3.0Al1.0O10](OH)8 (–8696 ± 13 kJ/mol) from elements were determined. The values of the standard entropies and the Gibbs energies of formation of the studied natural minerals as well as thermodynamic properties of Mg–Fe chlorites of theoretical composition were estimated. 相似文献
23.
I. V. Pekov V. O. Yapaskurt S. N. Britvin M. F. Vigasina I. S. Lykova N. V. Zubkova S. V. Krivovichev E. G. Sidorov 《Geology of Ore Deposits》2017,59(7):601-608
A new mineral romanorlovite has been found in the upper, moderately hot zones of two fumaroles, Glavnaya Tenoritovaya (Major Tenorite) and Arsenatnaya (Arsenate), located at the second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. It is associated with avdoninite in both fumaroles, and in Glavnaya Tenoritovaya, it is also associated with belloite, sylvite, carnallite, mitscherlichite, sanguite, chlorothionite, eriochalcite, chrysothallite, and mellizinkalite. Romanorlovite occurs as prismatic, equant, or tabular tetragonal crystals up to 0.1 mm in size, crystal clusters up to 0.5 mm, and crusts up to 2 × 2 mm in area. The mineral is transparent with vitreous luster. Its color varies from yellow-brown to dark brown, and tiny crystals are honey- or golden-yellow. Cleavage is not observed. Romanorlovite is brittle. The Mohs hardness is ca ~3. The calculated density varies from 2.72 to 2.79 g/cm3 depending on the content of admixed Pb. The mineral is optically uniaxial (–), ω = 1.727(3), ε = 1.694(2). The Raman spectrum has been reported. The chemical composition of the holotype sample (wt %; electron microprobe data, contents of О and H calculated by stoichiometry) is as follows: 21.52 K, 0.89 Pb, 28.79 Cu, 0.02 Zn, 44.74 Cl, 4.85 Ocalc, 0.41 Hcalc, total 101.22. Its empirical formula calculated based on Cl25 with (ОН)4(Н2О)2 is K10.90Pb0.09Cu8.97Zn0.01Cl25(OH)4 · 2H2O. The simplified formula is K11Cu9Cl25(OH)4 · 2H2O (Z = 4). Romanorlovite is tetragonal, space group[ I4/mmm. The unit cell parameters are (1) holotype: a = 17.5804(7), c = 15.9075(6) Å, V = 4916.5(3) Å3; (2) the sample enriched in Pb on which the crystal structure was refined: a = 17.5538(19), c = 15.8620(17) Å, V= 4887.7(9) Å3. The strongest reflections of the powder XRD pattern (d, Å–I[hkl]) are 12.48–56[110], 11.74–36[101], 8.80–100[200], 7.97–34[002], 6.71–40[112], 3.165–32[512], 2.933–80[215, 433], 2.607–38[514]. The mineral is named in honor of Roman Yu. Orlov (1929-2005), Russian mineralogist and physicist, who worked in the Department of Mineralogy, Moscow State University. 相似文献
24.
L. P. Ogorodova L. V. Melchakova M. F. Vigasina D. A. Ksenofontov I. A. Bryzgalov 《Geochemistry International》2018,56(4):397-401
The thermochemical study of natural hydrous calcium and iron phosphate, anapaite Ca2Fe(PO4)2 · 4H2O (Kerch iron ore deposit, Crimea, Russia), was carried out using high-temperature melt solution calorimetry with a Tian-Kalvet microcalorimeter. The enthalpy of formation of the mineral from elements was obtained to be Δ f Hel°(298.15 K) =–4812 ± 16 kJ/mol. The values of the standard entropy and the Gibbs energy of anapaite formation are S°(298.15 K) = 404.2 J/K mol and Δ f Gel°(298.15 K) =–4352 ± 16 kJ/mol, respectively. 相似文献
25.
L. P. Ogorodova M. F. Vigasina O. V. Kononov N. N. Koshlyakova D. A. Ksenofontov D. A. Khanin V. D. Shcherbakov L. V. Mel’chakova 《Geochemistry International》2018,56(8):865-869
The paper reports pioneering data on the calorimetrically determined enthalpy of formation from elements of cuspidine, Ca fluordiorthosilicate Ca4Si2O7F2, from the Tyrny-Auz Mo–W deposit in Kabardino- Balkaria, Russia. The data were obtained by high-temperature melt solution calorimetry. The determined value is ΔfHel° (298.15 K) =–5190 ± 13 kJ/mol. The paper reports estimated S°(298.15 K) and ΔfGel° (298.15 K) of cuspidine. 相似文献
26.
I. A. Kiseleva L. P. Orogodova V. V. Krupskaya L. V. Melchakova M. F. Vigasina I. Luse 《Geochemistry International》2011,49(8):793-801
The enthalpies of formation of kaolinite and dickite were determined by high-temperature melt solution calorimetry to be ΔfH°(298.15 K) = −4118 ± 10 and −4127 ±10 kJ/mol, respectively. These data represent the first calorimetric confirmation of
the metastability of kaolinite with respect to dickite. 相似文献
27.
E. P. Kuznetsova R. G. Motenko M. F. Vigasina L. V. Mel’chakova 《Moscow University Geology Bulletin》2011,66(1):65-71
The results of the study of unfrozen water in frozen volcanic ashes of different ages and mineral compositions from Kamchatka
are discussed. The results of thermal analysis of chemical and granulometric composition are presented and discussed. 相似文献
28.
I.?A.?BaksheevEmail author V.?N.?Golubev V.?Yu.?Prokof’ev M.?F.?Vigasina V.?O.?Yapaskurt I.?A.?Bryzgalov 《Moscow University Geology Bulletin》2012,67(1):18-29
Quartz-tourmaline lenses, around which host granite is impregnated by uraninite, have been found among porphyritic granite
with large phenocrysts of the Urtui pluton in the Ttansbaikal krai framing the Strel’tsovka volcano-tectonic structure. Two
generations of tourmaline are distinguished. Most individual crystals belong to the first generation attributed to “fluor-schorl”;
tourmaline-II attributed to schorl occurs as thin rims overgrowing tourmaline-I. The major type of cation isomorphic substitution
in both tourmalines is Fe2+ → Mg. The Fe3+/Fetot value and Li content in the average sample are 2% and 80 ppm, respectively. The high F content, comparatively high Li, low
Fe3+/Fetot value, and character of cation isomorphic substitution indicate that the tourmaline relates to greisens. The combination
of these features allows one to distinguish greisen-type tourmaline-bearing rocks. The impregnated uranium mineralization
in granite of the Urtui pluton, one of the probable sources of uranium in economic U ore of the Strel’tsovka deposit, is suggested
to be caused by greisenization and the formation of quartz-tourmaline lenses. 相似文献
29.
30.
L. P. Ogorodova I. A. Kiseleva M. F. Vigasina L. V. Mel’chakova D. A. Ksenofontov I. A. Bryzgalov 《Geochemistry International》2017,55(7):669-673
The paper presents data on the thermochemical study (high-temperature melt calorimetry in a Tian–Calvet microcalorometer) of two natural Mg–Fe amphiboles: anthophyllite Mg2.0(Mg4.8Fe0.2 2+)[Si8.0O22](OH)2 from Kukh-i-Lal, southwestern Pamirs, Tajikistan, and gedrite Na0.4Mg2.0(Mg1.7Fe0.2 2+Al1.3)[Si6.3Al1.7O22](OH)2 from the Kola Peninsula, Russia. The enthalpy of formation from elements is obtained as–12021 ± 20 kJ/mol for anthophyllite and as–11545 ± 12 kJ/mol for gedrite. The standard entropy, enthalpy, and Gibbs energy of formation are evaluated for Mg–Fe amphiboles of theoretical composition. 相似文献