“…Weak bands at 714 and 716 cm −1 observed for ivanyukite-Na- C and Cu-rich ivanyukite-K may be attributed to the hydroxyl deformation (librational) mode (Frost and Kloprogge, 2003; Seki et al , 2020). The most intense bands at 595 and 599 cm −1 for rhombohedral and cubic ivanyukite-Na are significantly shifted (by ~60 cm −1 ) in comparison with the band at 533 cm −1 observed in the spectrum of Cu-rich ivanyukite-K and are related to the asymmetric bending vibrations of Si‒O bonds or overlapping stretching vibrations of Ti‒O bonds (Filippi et al , 2007; Celestian et al , 2013). This band also can be due to Cu−O stretching vibrations of mixed Cu−O−Ti stretching vibrations involving a Cu−O3 bond.…”
Section: Raman Spectroscopymentioning
confidence: 99%
“…The spectrum of cubic Cu-rich ivanyukite-K is similar to that of pharmacosiderite from Cornwall, England, taken from sample R050574 of the RRUFF project (Lafuente et al , 2015). The assignments of the absorption bands were made by analogy with structurally related pharmacosiderite (Frost and Kloprogge, 2003; Filippi, 2004; Filippi et al , 2007) and titanosilicates (Celestian et al , 2013; Pakhomovsky et al , 2018; Yakovenchuk et al , 2019) and are given in Table 2. Fig.…”
Section: Raman Spectroscopymentioning
confidence: 99%
“…The intense vibrational bands at 961, 929, 924 and 1030 cm ‒1 can be attributed to asymmetric stretching vibrations of SiO 4 tetrahedra, while the bands at 840, 844, and 845, 941 cm −1 are assigned to symmetric vibration modes involving the same bonds (Filippi, 2004; Celestian et al , 2013). Weak bands at 714 and 716 cm −1 observed for ivanyukite-Na- C and Cu-rich ivanyukite-K may be attributed to the hydroxyl deformation (librational) mode (Frost and Kloprogge, 2003; Seki et al , 2020).…”
“…Weak bands at 714 and 716 cm −1 observed for ivanyukite-Na- C and Cu-rich ivanyukite-K may be attributed to the hydroxyl deformation (librational) mode (Frost and Kloprogge, 2003; Seki et al , 2020). The most intense bands at 595 and 599 cm −1 for rhombohedral and cubic ivanyukite-Na are significantly shifted (by ~60 cm −1 ) in comparison with the band at 533 cm −1 observed in the spectrum of Cu-rich ivanyukite-K and are related to the asymmetric bending vibrations of Si‒O bonds or overlapping stretching vibrations of Ti‒O bonds (Filippi et al , 2007; Celestian et al , 2013). This band also can be due to Cu−O stretching vibrations of mixed Cu−O−Ti stretching vibrations involving a Cu−O3 bond.…”
Section: Raman Spectroscopymentioning
confidence: 99%
“…The spectrum of cubic Cu-rich ivanyukite-K is similar to that of pharmacosiderite from Cornwall, England, taken from sample R050574 of the RRUFF project (Lafuente et al , 2015). The assignments of the absorption bands were made by analogy with structurally related pharmacosiderite (Frost and Kloprogge, 2003; Filippi, 2004; Filippi et al , 2007) and titanosilicates (Celestian et al , 2013; Pakhomovsky et al , 2018; Yakovenchuk et al , 2019) and are given in Table 2. Fig.…”
Section: Raman Spectroscopymentioning
confidence: 99%
“…The intense vibrational bands at 961, 929, 924 and 1030 cm ‒1 can be attributed to asymmetric stretching vibrations of SiO 4 tetrahedra, while the bands at 840, 844, and 845, 941 cm −1 are assigned to symmetric vibration modes involving the same bonds (Filippi, 2004; Celestian et al , 2013). Weak bands at 714 and 716 cm −1 observed for ivanyukite-Na- C and Cu-rich ivanyukite-K may be attributed to the hydroxyl deformation (librational) mode (Frost and Kloprogge, 2003; Seki et al , 2020).…”
“…The band at 687 and weak band at 792 cm −1 are related to the symmetric stretching vibrations of the same bonds (Yakovenchuk et al , 2019). The most intense band at 597 cm −1 is related to the asymmetric bending vibrations of Si‒O bonds or overlapping stretching vibrations of Ti‒O bonds (Filippi et al , 2007; Celestian et al , 2013). The bands in the range 350‒500 cm −1 correspond to symmetric bending vibrations of O‒Si‒O bonds and overlapping stretching vibrations of Ti‒O bonds (Filippi et al , 2007; Pakhomovsky et al , 2018; Yakovenchuk et al , 2019).…”
For this study, the rare Cu-bearing silicate fumarolic assemblages from the Somma-Vesuvius volcano (Italy), characterized by the rare mineral litidionite, CuKNaSi 4 O 10 , were investigated.Recently other Cu-and Ti-bearing phases were found in these associations and here we report new data about these mineralizations, in which Ti-bearing litidionite occurs together with kamenevite, perovskite and rutile. Ti-bearing litidionite appears on the latest stages of partial crystallization of Ti-bearing silica glass. Incorporation of Ti 4+ into litidionite crystal structure was investigated in detail. The Raman spectra of Ti-bearing litidionite contain intense band at 597 cm −1 related to antisymmetric bending vibrations of Si-O bonds or overlapping stretching vibrations of Ti-O bonds. The bands in the range 350-500 cm −1 correspond to symmetric bending vibrations of O-Si-O bonds and overlapping stretching vibrations of Ti-O bonds. The crystal structure of Ti-litidionite has been refined in the P ̅ space group, a = 6.9699(7), b = 7.9953(10), c = 9.8227(10) Å, α = 105.186(9), β = 99.458(8), γ = 114.489(10) to R 1 = 0.064 for 1726 unique observed reflections. The refinement of the site-occupation factors confirmed the presence of Ti at five-coordinated M-site.The mean bond distance of 2.125 Å of M-site agrees with its refined occupancy (Ti 0.32 Cu 0.30 Ca 0.29 Fe 0.09 ) 1.00 . The incorporation of Ti into litidionite structure is accompanied by the complex heteropolyhedral substitution according to the scheme V Ti 4+ + VII-VIII □ + IV Al 3+ ↔ V Cu 2+ + VII-VIII (Na,K) + + IV Si 4+ . Two possible configurations for the phase with maximal TiO 2 content (12.06 wt% or 0.56 Ti apfu) CuTiK□Na 2 Si 7 AlO 20 (Z = 1) or CuTiK 2 Na□Si 7 AlO 20 (Z = 1) have been proposed.
“…Data pertaining to absorption strength, peak shape, position, and assignment of the bands in both the FTIR and Raman spectra are given in Tables 2a and 2b, respectively. Absorption bands were initially identified using data from Farmer (1974); specific assignments of those bands involving Ti-O-Si chains were made using data provided by Celestian et al (2013) for synthetic sitinakite, HNa 2 KTi 4 Si 2 O 14 ·4H 2 O, whose Raman spectrum is very similar to that of hogarthite. In general, the two vibrational spectra for hogarthite are quite similar to one another, such that absorption bands in both spectra can be discussed in terms of four major groupings: (1) bands at >3000 cm -1 ; (2) bands between 700 and 1200 cm -1 ; (3) bands between 400 and 700 cm -1 ; and (4) bands …”
Hogarthite, (Na,K) 2 CaTi 2 Si 10 O 26 ·8H 2 O, a new mineral of the lemoynite group, was discovered in vugs within metasomatically altered marble xenoliths in the Poudrette quarry, Mont Saint-Hilaire, La-Vallée-du-Richelieu RCM, Montérégie, Quebec, Canada. Crystals are bladed to blocky, average 0.05 × 0.15 × 2 mm in size, and range in color from tan to white to colorless. The mineral develops in dense, radiating crystal aggregates up to 0.5 × 3 mm in size, and is associated with calcite (several generations), quartz, haineaultite, labuntsovite-Mn, lemoynite, chabazite, and gmelinite-Na. Crystals are elongate along [100], flattened on {010} and are bounded by the forms pinacoid {010} (dominant), pinacoid {100} (minor), and pinacoid {001} (minor). The mineral has a white streak, is non-fluorescent under short-, medium-, and long-wave ultraviolet radiation, is translucent, and has a satiny to silky to subvitreous luster. It has a brittle fracture, a perfect {010} cleavage, a hackly to splintery fracture, an estimated hardness of 4, and D calc = 2.40(1) g/cm 3 . Hogarthite is biaxial (+) with α 1.567(1), β 1.591 (1), and γ 1.618(1) with 2V meas = 87(1)º and 2V calc = 88(1)º. The optical orientation is X = b, Y ˄c = 15º (measured in the obtuse angle β), Z = a. A total of 21 analyses, obtained from seven crystals, gave an average (range) of (wt.O, and the simplified formula is (Na, K) 2 CaTi 2 Si 10 O 26 ·8H 2 O. The presence of (OH) and H 2 O were confirmed via refinement of the crystal-structure and data from combined FTIR and Raman spectroscopies. The mineral crystallizes in space group C2/m with a 10.1839(5), b 15.8244(6), c 9.1327(7) Å, β 104.463(2)º, V 1425.1(1) Å 3 , and Z = 2. The strongest six lines on the X-ray powder diffraction pattern [d in Å (I) (hkl)] are: 8.835 ((222,132). The crystal structure, refined to R = 0.049 for 1335 reflections (F o > 4σF o ), consists of a silicate component, composed of interconnected, non-planar 10-membered rings, arranged into thick slabs and stacked along [001]. These are interleaved with layers of independent TiO 6 octahedra, producing a framework of composition [TiSi 5 O 13 ] 2-. Numerous channels within the framework, notably the continuous ones developed by 10-membered silicate rings, are occupied by Na, Ca, and H 2 O groups. Hogarthite is considered to be a product of late-stage alkaline fluid enriched in SiO 2 and TiO 2 , and forming under conditions of low P at T < 200 ºC, possibly through crystallization of a gel.
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