The Crystal Chemistry and Structure of V-Bearing Silicocarnotite from Andradite–Gehlenite–Pseudowollastonite Paralava of the Hatrurim Complex, Israel
by
, , , ,
Evgeny V. Galuskin
1
,
Irina O. Galuskina
1,*
,
Maria Książek
2,
Joachim Kusz
2,
Yevgeny Vapnik
3 and
Grzegorz Zieliński
4 1
Institute of Earth Sciences, Faculty of Natural Sciences, University of Silesia, Będzińska 60, 41-200 Sosnowiec, Poland
2
Faculty of Science and Technology, University of Silesia, 75. Pułku Piechoty 1, 41-500 Chorzów, Poland
3
Department of Geological and Environmental Sciences, Ben-Gurion University of the Negev, P.O.B. 653, Beer-Sheva 84105, Israel
4
Polish Geological Institute—National Research Institute, Rakowiecka 4, 00-975 Warsaw, Poland
*
Author to whom correspondence should be addressed.
Minerals 2024, 14(12), 1301; https://doi.org/10.3390/min14121301
Submission received: 25 October 2024
/
Revised: 27 November 2024
/
Accepted: 9 December 2024
/
Published: 23 December 2024
(This article belongs to the Special Issue Isomorphism, Chemical Variability, and Solid Solutions of Minerals and Related Compounds, 2nd Edition)
Abstract
:Silicocarnotite, Ca5[(PO4)(SiO4)](PO4), was first described from slag over 140 years ago. In 2013, it was officially recognised as a mineral after being discovered in the larnite–gehlenite hornfels of the pyrometamorphic Hatrurim Complex. This paper describes the composition and structure of V-bearing silicocarnotite, crystals of which were found in a thin paralava vein cutting through the gehlenite hornfels. A network of thin paralava veins a few centimetres thick is widespread in the gehlenite hornfels of the Hatrurim Basin, Negev Desert, Israel. These veins, typically coarse crystalline rock and traditionally referred to as paralava, have a symmetrical structure and do not contain glass. Silicocarnotite in the paralava, whose primary rock-forming minerals are gehlenite, flamite, Ti-bearing andradite, rankinite and pseudowollastonite, was a relatively late-stage high-temperature mineral, crystallising at temperatures above 1100 °C. It formed from the reaction of a Si-rich residual melt with pre-existing fluorapatite. A single-crystal structural study of silicocarnotite (Pnma, a = 6.72970(12) Å, b = 15.5109(3) Å, c = 10.1147(2) Å) suggests that the phenomenon of Ca1 position splitting observed in this mineral is most likely related to the partial ordering of Si and P in the T2O4 tetrahedrons. Raman studies of silicocarnotite with varying vanadium content have shown that phases with V2O5 content of 3–5 wt.% exhibit additional bands at approximately 864 cm−1, corresponding to vibrations of ν1(VO4)3−.
1. Introduction
Silicocarnotite, Ca5[(PO4)(SiO4)](PO4), was first described as an artificial phase from slag 140 years ago [1]. It recently achieved mineral status, while retaining its historical name, after being discovered in the larnite–gehlenite pyrometamorphic rocks of the Hatrurim Complex, where it forms a solid solution with ternesite, Ca5(SiO4)2(SO4) [2]. The name silicocarnotite was introduced by Kroll in 1911 [3] and has since been widely used by many authors to describe artificial phases of the composition Ca5(PO4)2(SiO4) [4,5,6,7,8,9,10,11,12]. A partially ordered structure of silicocarnotite in which Si occupies only one type of tetrahedron (T2O4) and P occupies two (T1O4 and T2O4), Ca5[(PO4)(SiO4)](PO4), was solved in 1971 [13]. The first structural studies of artificial silicocarnotite revealed a phenomenon associated with the splitting of Ca1 positions, a characteristic later observed in natural silicocarnotite and P-bearing ternesite [2]. For synthetic blue silicocarnotite containing 2.5 wt. % V2O5, it has been suggested that a small impurity of V4+ may occupy the Ca1 position [13].
Colourless silicocarnotite crystals with a pink tint were found in thin veins of Ti-bearing andradite–gehlenite–pseudowollastonite paralava in gehlenite hornfels of the Hatrurim Complex. The crystals measured up to 0.4 mm in size and contained up to ~5 wt.% V2O5 and up to 0.6 wt.% SO4. This paper presents the results of a compositional study of these silicocarnotite crystals, alongside data from single-crystal structural and Raman studies. Additionally, the genetic mechanisms and conditions of silicocarnotite formation are discussed, as well as the phenomenon of Ca1 position splitting in silicocarnotite and its underlying causes.
2. Methods
The morphology and composition of silicocarnotite and associated minerals were studied using an Olympus optical microscope, a Quanta 250 scanning electron microscope (Institute of Earth Sciences, Faculty of Natural Sciences, University of Silesia, Sosnowiec, Poland) and an electron microprobe analyser (Cameca SX100, Micro-Area Analysis Laboratory, Polish Geological Institute–National Research Institute, Warsaw, Poland). Chemical analyses were performed in WDS mode (wavelength-dispersive X-ray spectroscopy, settings: 15 kV, 20 nA and ∼1 μm beam diameter) using the synthetic and natural standards: SiKα–diopside; CaKα–fluorapatite; SKα–baryte; VKα–metallic V; PKα–fluorapatite; MnKα–rhodonite; NaKα–albite.
A single-crystal X-ray study of a silicocarnotite crystal was carried out using a SuperNova diffractometer with a mirror monochromator (MoKα, λ = 0.71073Å) and an Atlas CCD detector (formerly Agilent Technologies, currently Rigaku Oxford Diffraction) at the Institute of Physics, University of Silesia, Poland. The structure of silicocarnotite was refined using the SHELX-2019/2 program [14]. The crystal structure was refined starting from the atomic coordinates of the holotype silicocarnotite [2].
The Raman spectra of silicocarnotite were recorded on a WITec alpha 300R confocal Raman microscope (Department of Earth Sciences, University of Silesia, Poland) equipped with an air-cooled solid laser (488 nm) and a CCD camera operating at –61 °C. A Zeiss LD EC Epiplan-Neofluan DIC-100/0.75NA air objective was used. Raman scattered light was focused onto a multimode fibre and monochromator with a 1800 mm−1 grating. The laser power at the sample position was ~40 mW. A total of 15 scans were collected with an integration time of 3 s and a resolution of ~2 cm−1 and averaged. The spectrometer monochromator was calibrated using the Raman scattering line of a silicon plate (520.7 cm−1).
3. Background Information
Gehlenite hornfels, along with spurrite marbles and larnite pseudoconglomerates, form the main types of rocks in the pyrometamorphic Hatrurim Complex, which is distributed along the Dead Sea rift in the territories of Israel, Palestine and Jordan [15,16]. Their formation was driven by combustion processes in a sedimentary protolith, though the genesis of the Hatrurim Complex is still subject to debate [17,18,19]. Various types of paralava are also present. The term ”paralava”, which has been employed by Hatrurim Complex researchers since Sharygin [20], refers to thin, coarse-crystalline veins (typically up to 5 cm thick) that are widespread in the gehlenite hornfels of the Hatrurim Complex and are composed of the same minerals as the host rock. These veins are notable for their symmetrical–zonal structure, which demonstrates geometric selection, and the practical absence of glass.
4. Occurrence of Silicocarnotite
Silicocarnotite was found in a 1 cm thick andradite–gehlenite–pseudowollastonite paralava vein within gehlenite hornfels (Figure 1a–c) near the headwaters of a tributary of Wadi Zohar (31°11′10.6″ N, 35°16′29″ E) in the Hatrurim Basin, Israel. Within a 500 m radius of its occurrence, other outcrops of gehlenite hornfels contain thin paralava veins in which two new minerals have been discovered: mazorite, Ba3(PO4)2 [21], and fluoralforsite, Ba5(PO4)3F [22].
The main minerals of the paralava are gehlenite (with a peripheral zone enriched with alumoåkermanite), Ti-bearing andradite, rankinite, fluorapatite, flamite, pseudowollastonite and kalsilite. The paralava has a symmetrical structure, and the growth direction of the rock-forming minerals is subperpendicular to the vein walls, demonstrating geometric selection. This phenomenon is particularly evident in the dark funnel-shaped garnet crystals growing from the walls of the vein. In the centre of the vein, there are differently oriented crystals of pseudowollastonite, rankinite and kalsilite crystals up to 0.5 cm in size (Figure 1a,b and Figure 2A). Accessory and rare minerals, which usually form small aggregates (inclusions) within or between the rankinite and pseudowollastonite crystals, are represented by minerals of the aradite–zadovite series, vorlanite, U-bearing pseudowollastonite, spinel of the jacobsite–magnesioferrite series, perovskite, barioferrite, gurimite and baryte (Figure 1d). The host hornfels consists of gehlenite, flamite, Ti-bearing andradite and rare rankinite, with accessory Mn-bearing magnesioferrite. Flamite is partially replaced by heterogeneous S-bearing silicocarnotite and hydrous silicates, which is reflected in the brightening of the rock (Figure 1a). The reaction relationships between flamite (Ca:Si = 2:1), rankinite (Ca:Si = 1.5:1) and pseudowollastonite (Ca:Si = 1:1) indicate a tendency for Si to accumulate in later melt stages (Figure 1e). This process leads to the formation of silicocarnotite reaction rims on fluorapatite crystals and silicocarnotite crystals synchronous with the late garnet zones (Figure 1b and Figure 2B).
5. Chemical Composition of Silicocarnotite
The majority of silicocarnotite, which appears in the form of reaction rims on fluorapatite (Figure 1c) and crystals with morphological evidence of simultaneous growth with andradite (Figure 2B), has a consistent stoichiometric composition, with vanadium not exceeding 1–2 wt.% V2O5. However, in the central part of the paralava (Figure 1c), a 0.4 mm transparent crystal of silicocarnotite with a pink tint was found in which the vanadium content was higher, reaching 5 wt.% V2O5, with a tendency to increase towards the edge of the crystal (Table 1). This crystal was used for single-crystal structural and Raman studies.
In silicocarnotite, which has the formula X5(T1O4)(T2O4)2 = Ca5(PO4)[(PO4)(SiO4)], vanadium can enter either the T1O4 tetrahedron or the T2O4 tetrahedron. There are three main possible variants of the empirical crystal chemical formula:
- Ca5[(PO4)0.80(VO4)0.20]∑1.00[(SiO4)1.00(PO4)0.97(SO4)0.03]∑2.00;
- Ca(PO4)[(SiO4)1.00(PO4)0.77(VO4)0.20(SO4)0.03]∑2.00;
- Ca5[(PO4)0.90(VO4)0.10]∑1.00[(SiO4)1.00(PO4)0.87(VO4)0.10(SO4)0.03]∑2.00.
We hoped that structural studies of single crystals would help us choose the most probable crystal chemical formula, but this hope turned out to be not entirely justified (see below). Raman studies of silicocarnotites with different V content showed that, even at small V content (a few per cent of V2O5 wt.%), it is possible to separate V-free and V-bearing silicocarnotite.
6. Raman Spectroscopy Study of Silicocarnotite
The Raman spectra of V-low silicocarnotite (V2O5 ≤ 1wt. %) exhibit the following bands (cm−1) (Figure 3a): 1007 ν1(SO4), 951 ν1(PO4), 846 ν1(SiO4), 628 ν4(PO4), 582 ν4(SiO4), 469 and 397 ν2(PO4) and ν2(SiO4), 218 ν(Ca-O) ([23,24,25,26]. The strongest bands reflect the vibrations of (SiO4) and (PO4) tetrahedra. The V-bearing spectrum of silicocarnotite (Figure 3b) shows an additional line at 864 cm−1 corresponding to the ν1(VO4)3- vibrations and partially overlapping with the ν3(SiO4)4- line [26].
7. Structural Investigation of V-Bearing Silicocarnotite
Single-crystal X-ray diffraction data were collected using a fragment of silicocarnotite crystal 0.1 × 0.08 × 0.03 mm3 in size using a SuperNova diffractometer. The experimental details and refinement data are summarised in Table 2, Table 3, Table 4 and Table 5. In the structure of silicocarnotite, there are two types of isolated tetrahedra, T1O4 and T2O4, between which there are calcium positions (Figure 4). Tetrahedron T1O4 is in the mirror plane, and position T1 is coordinated by O1, O2 and two O3 atoms. The T2 position is coordinated by O4, O5, O6 and O7. The average T1-O and T2-O distances are 1.559 Å and 1.597 Å, respectively (Table 5), and are slightly larger than the same distances in V-free silicocarnotite, T1-O = 1.549 Å and T2-O = 1.5895 Å [2]. This confirms the occupancy of the T1 position by P and of the T2 position by P and Si and indicates a probable vanadium admixture in both positions. Unfortunately, the exact determination of the amount of vanadium in the tetrahedral positions was beyond the sensitivity of the method used, so we calculated the position occupancy calculated from the theoretical distances P-O = 1.53 Å, Si-O = 1.62 Å and V-O = 1.715 Å [27] (Table 3) and fitted the structural model with the most realistic bond valence sum (BVS) values of 5.02e- and 4.49e- for T1 and T2, respectively (Table 5). In this case, the structural formula of silicocarnotite is Ca5[(PO4)0.9(VO4)0.1] [(SiO4)0.5 (PO4)0.45 (VO4)0.05]2. This formula is close to the empirical formula (Ca4.98Mn2+0.01Na0.01)Σ5.00[(PO4)0.90(VO4)0.10]∑1.00[(SiO4)1.00(PO4)0.87(VO4)0.10(SO4)0.03]∑2.00 (Table 1). The silicocarnotite studied by us has the most pronounced manifestation of the Ca1 position splitting phenomenon observed in the known data [2], splitting into well-resolved Ca1(0.86) and Ca1A(0.14) positions located at the Ca1–Ca1A = 0.352 Å distance. The reader will find in the Supplementary Materials two CIFs with data of the silicocarnotite structure refinements with fixed occupation of the tetrahedra T1 (0.9P/0.1V) and T2 (0.5Si/0.45P/0.05V) (the model we adopted) and with refined occupation of the T1 (0.966(4)P/0.034(4)V) and T2 (0.5Si fixed/0.469(3)P/0.031(3)V).
8. Discussion
8.1. Genetic Aspects of the Hornfels and Paralava Formation
Gehlenite hornfels, as larnite rocks of the Hatrurim Complex, form during the high temperature stage of pyrometamorphism (T > 1000 °C) and, unlike spurrite marbles, do not contain carbonates. The protolith of the hornfels is an inhomogeneous bituminous carbonate–clay rock of the Ghareb formation, which contains pyrite framboides and phosphorised bone remains [30]. Hornfels has a fine-grained texture and its formation during the heating of the protolith to temperatures above 1000 °C proceeds by the “the generally accepted mechanism for the formation of metamorphic rocks”. During the metamorphism phase, substitution occurs via the “solid-solid” mechanism with the participation of intergranular capillary fluids. The conditions of pyrometamorphic rock formation (sanidinite facies––very high temperature and low pressure) practically exclude the presence of long-lived intergranular fluids. In typical metamorphism, these fluids facilitate the dissolution of protolith minerals and the simultaneous formation of new stable phases. Here, it is likely that intergranular melt was the reactive agent in the formation of pyrometamorphic rocks. The presence of intergranular melt has already been demonstrated by the example of the flamite–gehlenite rock of the Hatrurim Complex, where there was a residual melt between rounded crystals of flamite, the crystallisation of which led to the formation of a fluormayenite–flamite eutectic [31].
The mechanism of formation of the thin network of paralava veins in hornfels can be presented as follows. The formation of gehlenite hornfels after sedimentary protolith during the pyrometamorphic process was accompanied by the appearance of fractures, into which intergranular melt was extruded. Paralava veins often show a symmetrical structure and a pronounced geometric selection during the growth of the minerals. The veins have no roots and are represented by almost completely crystalline material. They are visually similar to pegmatite or alpine veins with a symmetrical structure. Crystallisation of the melt in the fractures within the hornfels took a relatively long time in the thermal conditions of the hornfels, so there is no glass in the paralava. Part of the melt extruded into the fractures was unmixed and locally enriched with rock-forming minerals incompatible elements and leading to the formation of small (1–2 mm) inclusions of melt enriched with Ba, Ti, Fe, U, V, P, Mn, Nb and Sb inside the veins [32]. The crystallisation of such inclusions led to the formation of a large number of rare and new minerals, including walstromite, zadovite, aradite, vorlanite, khesinite, gurimite and others. In the central part of the veins, kalsilite, a rare mineral for hornfels, was found, as well as nepheline and combeite. It is thought that alkali accumulated in the intergranular melt, lowering its crystallisation temperature and prolonging its existence. Therefore, paralavas of this type formed from a practically motionless, heterogeneous melt, where minerals crystallised from the walls onto early formed seeds of structurally similar minerals.
8.2. Silicocarnotite Formation
Silicocarnotite is a late-forming mineral in pyrometamorphic rocks. Its occurrence in paralavas is associated with the accumulation of Si in the residual high-temperature melt, which reacts with previously formed minerals, usually fluorapatite (Figure 1c). In addition, silicocarnotite is formed in hornfels after P-bearing flamite. Experimental data indicate that its crystallisation temperature exceeds 1100 °C [26]. The peculiar Si-metasomatism seen in the paralava is related to the crystallisation sequence of the rock-forming minerals, whose sedimentary protolith and host hornfels were both characterised by low Si content. The early crystallisation of gehlenite, Ca2Al2SiO7 (Ca:Si = 2:1), flamite αH’- Ca2SiO4 (Ca:Si = 2:1) and andradite with a high content of schorlomite Ca3Ti2(R3+Si)O12 end-member and fluorapatite led to the accumulation of silicon in the system and the formation of relatively later phases with higher silicon content. This is indicated by the crystallisation sequence flamite → rankinite → pseudowollastonite (Figure 1e). It cannot be excluded that the reaction of Si-rich melt with previously formed fluorapatite and the formation of silicocarnotite was caused by a short-term temperature rise, which is characteristic of non-stationary combustion processes.
The behaviour of P in pyrometamorphic processes of paralava formation requires further study, but it is clear that local increases in its activity, both in time and space, can occur as a result of the transformation of early high-temperature, P-bearing flamite, αH’- (Ca,Na,K)2(Si,P)O4, to P-free larnite, β- Ca2SiO4. Phosphorus also tends to accumulate in melt heterogeneities–peculiar inclusions enriched in non-compactable elements, the crystallisation of which leads to the formation of exotic P-bearing minerals such as mazorite or zadovite, associated with “rock-forming” minerals with unusual impurities, such as U-bearing pseudowollastonite (Figure 1d). It can be argued that P derived from numerous bones remains in the sedimentary protolith, and phosphorite inclusions, along with calcium, are mobile elements, leading to the large number of phosphorus-bearing phases in different types of pyrometamorphic rocks of the Hatrurim Complex.
8.3. The Phenomenon of Splitting of the Ca1 Position in the Structure of Silicocarnotite
Figure 5 shows the position of the mutually exclusive sites of Ca1 (86%) and Ca1A (14%) coordinated by 8 and 9 oxygens, respectively, which in turn are involved in the coordination of the tetrahedral positions T1 and T2. It is very likely that a tetrahedral cation is involved in the splitting of the Ca1 position. In position T1, there is only phosphorus with a small amount of vanadium. It should be stressed that the phenomenon of splitting of the Ca1 position has previously been observed in V-free silicocarnotite [2]. This may indicate that V at the tetrahedral positions and P at the T1 position do not have a significant effect on the Ca1 position splitting.
The positions of Ca1 and Ca1A are symmetrically located between four tetrahedra T2, which are filled with P and Si = 50/50. Considering that the local charge balance determines the need to fill two tetrahedra with Si and the other two with P, we can assume that the phenomenon of the splitting of the Ca1 position is related to the partial ordering of Si and P in the T2 tetrahedrons; for example, the two upper T2 tetrahedra (if we look at Figure 5) are occupied by P and the two lower ones by Si.
9. Conclusions
- The formation of a paralava vein network in hornfels is associated with the extrusion of portions of intergranular melt into fractures, whose crystallisation leads to the formation of thin, coarse-crystalline veins with a symmetrical structure, demonstrating growth geometric selection.
- The silicocarnotite in the paralava is a relatively late-stage, high-temperature mineral formed by the reaction of the Si-enriched residual melt with fluorapatite formed at an earlier stage.
- The splitting of the Ca1 position in silicocarnotite’s structure is probably related to the partial ordering of Si and P in T2 tetrahedra.
Supplementary Materials
Supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/min14121301/s1, CIF of silicocarnotite.
Author Contributions
E.V.G. and I.O.G. contributed to the writing of the draft manuscript; Y.V., I.O.G. and E.V.G. participated in the fieldwork which led to the discovery of silicocarnotite; E.V.G., I.O.G. and Y.V. conducted the petrological investigations, measured the composition of silicocarnotite and associated minerals, performed the Raman and optical studies and selected grains for the structural investigations; J.K. and M.K. performed the SC XRD investigation and refined the structure of silicocarnotite; G.Z. conducted the microprobe studies. All authors have read and agreed to the published version of the manuscript.
Funding
These investigations were partly supported by the National Science Centre of Poland Grant No. 2021/41/B/ST10/00130 (EG and IG).
Data Availability Statement
The original contributions presented in this study are included in the article/Supplementary Materials. Further inquiries can be directed to the corresponding authors.
Acknowledgments
The authors would like to thank anonymous reviewers for their remarks and comments that improved an earlier version of the manuscript.
Conflicts of Interest
The authors declare no conflicts of interest.
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Figure 1.
(a) Polished sample with gehlenite–andradite–pseudowollastonite paralava in hornfels. Hornfels––the dark part represents weakly altered gehlenite–flamite rock, the light part altered hornfels in which flamite is replaced by silicocarnotite and Ca-hydroxides, and gehlenite by hydrogarnet. In the paralava, the minerals are coloured as follows: Ti-bearing andradite––dark brown, gehlenite––light brown, wollastonite, flamite and pseudowollastonite––white. (b) A polished thin-section from the central part of the sample is shown in Figure 1a. (c) Silicocarnotite forms single crystals and rims on fluorapatite crystals. A crystal of V-bearing silicocarnotite is marked in the lower part of the image. (d) U-bearing pseudowollastonite, vorlanite and aradite aggregate in a large pseudowollastonite grain. (e) Reaction zone of rankinite between flamite and pseudowollastonite. Ara = aradite, Adr = andradite, Fmt = flamite, Fap = fluorapatite HSi = Ca-hydrosilicate, Gh = gehlenite, Jcb = jacobsite, Pwo = pseudowollastonite, Rnk = rankinite, Scnt = silicocarnotite, Vrl = vorlanite.
Figure 1.
(a) Polished sample with gehlenite–andradite–pseudowollastonite paralava in hornfels. Hornfels––the dark part represents weakly altered gehlenite–flamite rock, the light part altered hornfels in which flamite is replaced by silicocarnotite and Ca-hydroxides, and gehlenite by hydrogarnet. In the paralava, the minerals are coloured as follows: Ti-bearing andradite––dark brown, gehlenite––light brown, wollastonite, flamite and pseudowollastonite––white. (b) A polished thin-section from the central part of the sample is shown in Figure 1a. (c) Silicocarnotite forms single crystals and rims on fluorapatite crystals. A crystal of V-bearing silicocarnotite is marked in the lower part of the image. (d) U-bearing pseudowollastonite, vorlanite and aradite aggregate in a large pseudowollastonite grain. (e) Reaction zone of rankinite between flamite and pseudowollastonite. Ara = aradite, Adr = andradite, Fmt = flamite, Fap = fluorapatite HSi = Ca-hydrosilicate, Gh = gehlenite, Jcb = jacobsite, Pwo = pseudowollastonite, Rnk = rankinite, Scnt = silicocarnotite, Vrl = vorlanite.
Figure 2.
(A) Zone of geometric selection in the margin of the paralava vein; the fragment in the frame is enlarged in Figure 2B. (B) Simultaneous growth of low-V silicocarnotite and garnet. Adr = andradite, Fap = fluorapatite, Gh = gehlenite, HSi = Ca-hydrosilicate, Rnk = rankinite, Scnt = silicocarnotite.
Figure 2.
(A) Zone of geometric selection in the margin of the paralava vein; the fragment in the frame is enlarged in Figure 2B. (B) Simultaneous growth of low-V silicocarnotite and garnet. Adr = andradite, Fap = fluorapatite, Gh = gehlenite, HSi = Ca-hydrosilicate, Rnk = rankinite, Scnt = silicocarnotite.
Figure 3.
Raman spectra of V-low (a) and V-bearing (b) silicocarnotite.
Figure 4.
Silicocarnotite structure. (a) Projection on (100), (b) projection on (001). T1O4-tetrahedra––grey, T2O4- tetrahedra––blue.
Figure 4.
Silicocarnotite structure. (a) Projection on (100), (b) projection on (001). T1O4-tetrahedra––grey, T2O4- tetrahedra––blue.
Figure 5.
Environment of Ca1 and Ca1A positions in the structure of silicocarnotite. T1O4-tetrahedra––grey, T2O4- tetrahedra––blue.
Figure 5.
Environment of Ca1 and Ca1A positions in the structure of silicocarnotite. T1O4-tetrahedra––grey, T2O4- tetrahedra––blue.
Table 1.
Microprobe analyses of V-bearing silicocarnotite.
| wt.% | Mean 14 | s.d. | Range |
|---|---|---|---|
| V2O5 | 3.73 | 0.92 | 2.10–5.04 |
| P2O5 | 25.50 | 1.94 | 23.60–31.52 |
| SiO2 | 12.10 | 1.33 | 7.60–12.93 |
| SO3 | 0.35 | 0.09 | 0.22–0.59 |
| CaO | 56.74 | 0.44 | 55.70–57.50 |
| MnO | 0.12 | 0.02 | 0.07–0.15 |
| Na2O | 0.05 | 0.04 | 0–0.15 |
| Total | 98.54 | ||
| Calculated on 12O | |||
| Ca | 4.98 | ||
| Mn2+ | 0.01 | ||
| Na | 0.01 | ||
| X | 5.00 | ||
| Si | 1.00 | ||
| Al | 0.00 | ||
| P5+ | 1.77 | ||
| S6+ | 0.03 | ||
| V5+ | 0.20 | ||
| T | 3.00 | ||
s.d.–standard deviation.
Table 2.
Crystal data and structure refinement details for silicocarnotite.
| Crystal Data | |
|---|---|
| Formula from refinement | Ca5.0P1.8Si1.0V0.2O12 |
| Crystal system | orthorhombic |
| Space group | Pnma (no. 62) |
| Unit-cell dimensions | a = 6.72970(12) Å |
| b = 15.5109(3) Å c = 10.1147(2) Å | |
| V = 1055.81(3) Å3 | |
| Z | 4 |
| Crystal size | 0.1 × 0.08 × 0.03 mm3 |
| Data collection | |
| Diffractometer | SuperNova with Atlas CCD |
| Radiation wavelength | MoKα, λ = 0.71073Å |
| Min. and max. theta | 3.64°, 30.0° |
| Reflection ranges | −9 ≤ h ≤ 9; −21 ≤ k ≤ 21; −10 ≤ l ≤ 14 |
| Refinement of structure | |
| Reflection measured | 10722 |
| No. of unique reflections | 1588 |
| No. of observed unique refl. [I > 2σ(I)] | 1519 |
| Refined parameters | 102 |
| Rint | 0.0185 |
| R1/Rall | 0.0150/0.0160 |
| wR | 0.0465 |
| GooF | 1.193 |
| Δρmin [e Å−3] | −0.353 |
| Δρmax [e Å−3] | 0.381 |
Table 3.
Atomic coordinates and isotropic displacement parameters (Å2) for silicocarnotite.
| Site | Atom | x | y | z | Ueq | Occ. |
|---|---|---|---|---|---|---|
| T1 | P/V | 0.02667 (7) | 0.25 | 0.57837 (4) | 0.01122 (9) | 0.90P + 0.10V |
| T2 | Si/P/V | 0.35145 (4) | 0.07224 (2) | 0.36902 (3) | 0.00640 (7) | 0.5Si + 0.45P + 0.05V |
| Ca1 | Ca | 0.0437(2) | 0.25 | 0.1870 (4) | 0.0130 (3) | 0.865 (11) |
| Ca1A | Ca | 0.0237 (10) | 0.25 | 0.1548 (11) | 0.0130 (3) | 0.135 (11) |
| Ca2 | Ca | 0.16841 (4) | −0.10614 (2) | 0.16488 (2) | 0.01257 (7) | 1 |
| Ca3 | Ca | 0.36809 (4) | 0.09193 (2) | 0.06483 (2) | 0.01071 (7) | 1 |
| O1 | O | 0.2571 (2) | 0.25 | 0.57911 (15) | 0.0214 (3) | 1 |
| O2 | O | 0.9332 (2) | 0.25 | 0.43633 (13) | 0.0151 (3) | 1 |
| O3 | O | 0.95749 (17) | 0.16537 (6) | 0.64730 (9) | 0.0186 (2) | 1 |
| O4 | O | 0.40853 (14) | 0.99420 (6) | 0.27349 (9) | 0.01279 (17) | 1 |
| O5 | O | 0.18753 (13) | 0.04394 (6) | 0.47428 (8) | 0.01051 (16) | 1 |
| O6 | O | 0.27474 (14) | 0.14911 (6) | 0.27677 (8) | 0.01191 (17) | 1 |
| O7 | O | 0.53013 (13) | 0.11089 (6) | 0.45472 (9) | 0.01346 (18) | 1 |
Table 4.
Anisotropic displacement parameters (Å2).
| Site | U11 | U22 | U33 | U23 | U13 | U12 |
|---|---|---|---|---|---|---|
| T1 | 0.0169 (2) | 0.00723 (18) | 0.00952 (18) | 0 | −0.00150 (15) | 0.0169 (2) |
| T2 | 0.00549 (13) | 0.00746 (14) | 0.00626 (13) | 0.00020 (9) | 0.00048 (9) | 0.00039 (10) |
| Ca1 | 0.0102 (3) | 0.00806 (16) | 0.0207 (8) | 0 | −0.0005 (4) | 0 |
| Ca1A | 0.0102 (3) | 0.00806 (16) | 0.0207 (8) | 0 | −0.0005 (4) | 0 |
| Ca2 | 0.01366 (12) | 0.01275 (12) | 0.01128 (12) | 0.00233 (9) | 0.00297 (8) | 0.00037 (8) |
| Ca3 | 0.00917 (11) | 0.00957 (12) | 0.01340 (12) | −0.00121 (8) | 0.00203 (8) | 0.00032 (8) |
| O1 | 0.0236 (7) | 0.0140 (6) | 0.0267 (7) | 0 | −0.0090 (6) | 0 |
| O2 | 0.0197 (6) | 0.0112 (6) | 0.0144 (6) | 0 | −0.0010 (5) | 0 |
| O3 | 0.0306 (6) | 0.0128 (4) | 0.0123 (4) | 0.0019 (3) | 0.0042 (4) | −0.0025 (4) |
| O4 | 0.0132 (4) | 0.0127 (4) | 0.0124 (4) | −0.0010 (3) | 0.0008 (3) | 0.0021 (3) |
| O5 | 0.0085 (4) | 0.0119 (4) | 0.0112 (4) | 0.0003 (3) | 0.0002 (3) | −0.0006 (3) |
| O6 | 0.0131 (4) | 0.0115 (4) | 0.0111 (4) | −0.0001 (3) | −0.0007 (3) | 0.0009(3) |
| O7 | 0.0080 (4) | 0.0203 (5) | 0.0121 (4) | 0.0010 (3) | 0.0001 (3) | −0.0004 (3) |
Table 5.
Selected bond lengths (Å) and BVS* calculation for silicocarnotite.
| Atom | -Atom | Distance | Atom | -Atom | Distance | ||
|---|---|---|---|---|---|---|---|
| T1 | -O1 | 1.5505 (17) | T2 | -O5 | 1.5948 (9) | ||
| -O3 | 1.5576 (10) | ×2 | -O4 | 1.5959 (9) | |||
| -O2 | 1.5686 (14) | -O7 | 1.5990 (9) | ||||
| mean | 1.559 | -O6 | 1.5996 (9) | ||||
| BVS | 5.02 | mean | 1.597 | ||||
| BVS | 4.49 | ||||||
| Ca1 | -O6 | 2.386 (2) | ×2 | Ca1A | -O6 | 2.395(4) | ×2 |
| -O6 | 2.4204 (12) | ×2 | -O6 | 2.613(9) | ×2 | ||
| -O7 | 2.592 (2) | ×2 | -O7 | 2.425 (5) | ×2 | ||
| -O2 | 2.629 (3) | -O1 | 2.969 (12) | ||||
| -O2 | 2.9029 (16) | -O2 | 2.906 (6) | ||||
| mean | 2.541 | -O2 | 2.912 (11) | ||||
| BVS | 1.56 | mean | 2.628 | ||||
| BVS | 0.28 | ||||||
| Ca2 | -O4 | 2.4225 (9) | Ca3 | -O4 | 2.6127 (9) | ||
| -O4 | 2.4980 (9) | -O5 | 2.3092 (9) | ||||
| -O5 | 2.3642 (8) | -O5 | 2.3289 (9) | ||||
| -O7 | 2.5118 (8) | -O6 | 2.4034 (9) | ||||
| -O1 | 2.4462 (6) | -O7 | 2.3018 (9) | ||||
| -O3 | 2.2743 (9) | -O2 | 2.4906 (4) | ||||
| -O3 | 2.6860 (11) | -O3 | 2.5027 (10) | ||||
| mean | 2.458 | mean | 2.421 | ||||
| BVS | 1.92 | BVS | 2.13 | ||||
| BVS | BVS | ||||||
| O1 | 1.88 | O5 | 2.19 | ||||
| O2 | 1.95 | O6 | 2.02 | ||||
| O3 | 2.04 | O7 | 1.93 | ||||
| O4 | 1.83 |
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Galuskin, E.V.; Galuskina, I.O.; Książek, M.; Kusz, J.; Vapnik, Y.; Zieliński, G. The Crystal Chemistry and Structure of V-Bearing Silicocarnotite from Andradite–Gehlenite–Pseudowollastonite Paralava of the Hatrurim Complex, Israel. Minerals 2024, 14, 1301. https://doi.org/10.3390/min14121301
AMA Style
Galuskin EV, Galuskina IO, Książek M, Kusz J, Vapnik Y, Zieliński G. The Crystal Chemistry and Structure of V-Bearing Silicocarnotite from Andradite–Gehlenite–Pseudowollastonite Paralava of the Hatrurim Complex, Israel. Minerals. 2024; 14(12):1301. https://doi.org/10.3390/min14121301
Chicago/Turabian StyleGaluskin, Evgeny V., Irina O. Galuskina, Maria Książek, Joachim Kusz, Yevgeny Vapnik, and Grzegorz Zieliński. 2024. "The Crystal Chemistry and Structure of V-Bearing Silicocarnotite from Andradite–Gehlenite–Pseudowollastonite Paralava of the Hatrurim Complex, Israel" Minerals 14, no. 12: 1301. https://doi.org/10.3390/min14121301
APA StyleGaluskin, E. V., Galuskina, I. O., Książek, M., Kusz, J., Vapnik, Y., & Zieliński, G. (2024). The Crystal Chemistry and Structure of V-Bearing Silicocarnotite from Andradite–Gehlenite–Pseudowollastonite Paralava of the Hatrurim Complex, Israel. Minerals, 14(12), 1301. https://doi.org/10.3390/min14121301
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