Physics and Chemistry of Minerals https://doi.org/10.1007/s00269-018-0986-6

ORIGINAL PAPER

High-temperature Raman and FTIR study of aragonite-group carbonates

Xiang Wang1 · Yu Ye1 · Xiang Wu1 · Joseph R. Smyth2 · Yan Yang3 · Zengming Zhang4 · Zhongping Wang4

Received: 30 November 2017 / Accepted: 5 July 2018 © Springer-Verlag GmbH Germany, part of Springer Nature 2018

Abstract In situ high-temperature Raman and Fourier transform infrared spectra were measured for aragonite, strontianite, cerussite, and witherite at ambient pressure. The orthorhombic to trigonal phase transitions were observed by the vibrational spectra for aragonite and witherite, at the temperatures of 773 and 1150 K, respectively. The isobaric mode Grüneisen parameters (γiP), derived from this study, are compared with the isothermal mode Grüneisen parameters (γiT), calculated from the reported high-pressure measurements. The γiP and γiT parameters range from 0.46 to 3.43 for the lattice vibrational modes, whereas they are smaller than 0.4 for the internal vibrational modes of the ­CO3 group, consistent with the ­CO3 group serving as rigid bodies in the crystal structure. At high temperatures, the γiP parameters for in-plane and out-of-plane bending modes are systematically smaller than those for asymmetric and symmetric stretching modes of CO­ 3, implying that the O–C–O angles are even less sensitive to temperature than the C–O bond lengths. The intrinsic anharmonicities are also evaluated. The averaged anharmonic modes (ai_avg) are positive for cerussite, but negative for aragonite, strontianite and witherite. The intrinsic anharmonicity has quite different contributions to the equation of state and thermodynamic properties of cerussite, compared with other carbonate minerals, at the high temperatures and high pressures of mantle conditions.

Keywords Aragonite-group carbonate · Raman spectra · FTIR · Grüneisen parameters · Intrinsic anharmonicity

Introduction to explore the physical and chemical behavior of carbonates at high temperature and high pressure. ­CaCO3 is one of the Carbonates serve as potential carbon carriers for deep carbon most abundant carbonates in the Earth with three impor- reservoirs in the Earth’s interior (Dasgupta and Hirschmann tant naturally occurring polymorphs: calcite, aragonite, and 2010; Keppler et al. 2003; Marcondes et al. 2016). To under- vaterite. Calcite transforms to aragonite above 2 GPa at high stand the key roles in Earth’s carbon cycle, it is important temperatures (Ono 2005; Ono et al. 2007; Suito et al. 2001), and the post-aragonite phase transition happens at higher pressure conditions deep in the mantle (Smith et al. 2018; Electronic supplementary material The online version of this article (https​://doi.org/10.1007/s0026​9-018-0986-6) contains Lobanov et al. 2017; Oganov et al. 2006; Ono 2005). Arago- supplementary material, which is available to authorized users. nite and post-aragonite remain as the important phases for ­CaCO under mantle pressure–temperature conditions. * 3 Yu Ye The natural aragonite-group carbonates, including arago- [email protected] nite ­(CaCO3), strontianite ­(SrCO3), cerussite ­(PbCO3) and 1 State Key Laboratory of Geological Processes witherite (BaCO­ 3), are in space group Pmcn (De Villiers and Mineral Resources, China University of Geosciences, 1971; Speer 1983). In this orthorhombic crystal structure, Wuhan 430074, China the layers of 9-coordinated M­ 2+ cations, in an approximately 2 Department of Geological Sciences, University of Colorado, hexagonal-close-packed structure, alternate with layers of Boulder, CO 80309, USA planar ­CO3 groups, which are stacked perpendicular to the 3 School of Earth Sciences, Institute of Geology c axis. Extensive efforts have been devoted to explore the and Geophysics, Zhejiang University, Hangzhou 310027, physical and chemical properties of aragonite-group car- China bonates, such as crystal chemistry (e.g., Antao and Hassan 4 Physics Experiment Teaching Centers, University of Science 2009; Caspi et al. 2005; Holl et al. 2000; Pokroy et al. 2007; and Technology of China, Hefei 230026, China

Vol.:(0123456789)1 3 Physics and Chemistry of Minerals

Ye et al. 2012), equations of state (e.g., Antao and Hassan In this study, we will focus on vibrational modes of the 2010; Gao et al. 2016; Li et al. 2015; Oganov et al. 2006; aragonite-group carbonates by in situ high-temperature Palaich et al. 2016; Wang et al. 2015; Zhang et al. 2013), Raman and Fourier transform infrared (FTIR) spectrosco- elasticities (e.g., Biedermann et al. 2017; Liu et al. 2005; pies, and the new results will be compared with previous Sanchez-Valle et al. 2011), thermodynamics (e.g., Bissen- high-pressure measurements (e.g., Biellmann and Gillet galiyeva et al. 2012; Gurevich et al. 2001a, b; Ungureanu 1992; Catalli et al. 2005; Chaney et al. 2015; Lin and Liu et al. 2010), as well as phase transitions at high pressures 1997b, c; Kraft et al. 1991) ; we will evaluate and discuss the (e.g., Arapan and Ahuja 2010; Holl et al. 2000; Lin and Liu temperature and pressure dependence of vibration modes, 1997a; Ono 2005; Oganov et al. 2006). The thermal-elastic as well as the Grüneisen mode parameters and intrinsic properties at ambient condition are listed in Table 1, includ- anharmonic parameters, which are important for constrain- ing thermal expansion coefficients (α0, a0, a1), isothermal ing the thermodynamics of these carbonates at mantle pres- bulk moduli (KT0, KT′), elastic bulk moduli (KS0, G0), elastic sure–temperature conditions. velocities (VP, VS), and thermodynamic properties (entropy S0, heat capacity CP). Experimental methods

Table 1 Thermo-elastic properties of the aragonite-group carbonates Sample compositions at ambient condition Aragonite Strontianite Cerussite Witherite In this study, we used natural single crystals of aragonite and cerussite. The cerussite sample (University of Colorado Formula CaCO SrCO PbCO BaCO 3 3 3 3 collection Number 4552) is from Tsumeb, Namibia, with a V (Å3) 227.011(2)a 258.999(1)a 270.817(2)a 304.478(1)a 0 composition of Ca­ Pb CO (Ye et al. 2012). While ρ (g/cm3) 2.928(1)a 3.786(1)a 6.553(1)a 4.304(1)a 0.001 0.999 3 the aragonite sample is from Morocco, and the composi- α ­(10−6 K−1) 65(1)b 68(1)b 80(3)b 65(1)b 0 tion is analyzed using a JEOL JXA-8100 Electron Probe a ­(10−6 K−1)m 46(2)b 55(2)b 27(3)b 39(3)b 0 Micro Analyzer (EPMA) equipped with four wavelength- a ­(10−8 K−2)m 5.4(4)b 3.6(7)b 16.8(6)b 7.0(5)b 1 dispersive spectrometers (WDS), operating at an accelerat- K (GPa) 65.7(8)c 62(1)d 63(3)e,f 48(1)d T0 ing voltage of 15 kV and a beam current of 5 nA, with a K ′ 5.1(1)c 4d (fixed) 4e,f (fixed) 4d (fixed) T 10 µm spot size to minimize the sample damage and reduce K (GPa) 68.9(14)g 64(4)h 72.4h,o 58.7h,o S0 the X-ray intensity fluctuations (Zhang et al. 2017). In total, G (GPa) 35.8(2)g 31(1)h 26.8h,o 27.5h,o 0 eight points were selected for measurement, and the aver- V (km/s) 6.31(7)g 5.27(9)h 4.06(4)h 4.71(4)h P aged compositions (in oxides) with standard deviations are V (km/s) 3.50(2)g 2.86(3)h 2.02(2)h 2.53(2)h S listed in Table S1. Θ (K)n 517(17) 405(19) 284(14) 339(14) ac Strontianite and witherite are commercial powder from C (J/(mol K)) 83.1(1)i 86.52(15)j 87.07(9)k 93.24(17)l P Alfa-Aesar company (purity > 99.9%). These two powder S (J/(mol K)) 87.5(1)i 100.0(2)j 125.4(2)k 114.7(4)l 0 samples were wrapped in platinum foils (5 mm × 3.75 mm) γn 1.76(4) 1.90(6) 2.62(8) 1.73(5) and hot-pressed at 1.5 GPa and 1273 K for 48 h, using a a Antao and Hassan (2009) 150-ton non-end-loaded piston-cylinder press (Liu et al. b Ye et al. (2012) 2009) for the high-temperature Raman measurements. The c Litasov et al. (2017) quenched samples were further checked by Raman spectra d Wang et al. (2015) at ambient conditions, showing that they were still in the e Zhang et al. (2013) aragonite-type structure. f Gao et al. (2016) g Liu et al. (2005) Raman spectroscopy h Biedermann et al. (2017) i Ungureanu et al. (2010) In situ Raman spectra at low and high temperatures (ambient j Gurevich et al. (2001a) pressure) were obtained using a double-grating Jobin Yvon k Bissengaliyeva et al. (2012) spectrometer. A numeric aperture of NA = 0.35 and an Olym- f l Gurevich et al. (2001b) pus microscope lens with a focal distance = 20 mm were used m to focus the laser beam on the sample surface (Sui et al. 2016). Thermal expansion coefficient: a(T) = a0 + a1 × T n The carbonate samples were excited by the 514.5 nm line of an The acoustic Debye temperature (Θac) and the macroscopic Grü- −1 neisen number (γ) at ambient condition are calculated in this study Ar ion laser with spectral resolution of 2 cm . Sample pieces o 3 The KS0 and G0 moduli for cerussite and witherite are calculated on with a size of ~ 1 × 1 × 0.3 mm were selected for experiments, density functional theory from the natural single crystals of aragonite and cerussite, as

1 3 Physics and Chemistry of Minerals well as the hot-pressed strontianite and witherite. In low-tem- with the fitted peak positions listed in Table S2, which are perature measurements, each sample piece was loaded on the in general agreement with the previous studies (e.g., Gao sapphire window of a Linkam TS 600 heating/cooling stage, et al. 2016; Gillet et al. 1993; Lin and Liu 1997a, b, c; and low temperatures were obtained down to 100 K by cooling Martens et al. 2004; Minch et al. 2010a, b; Wehrmeister with liquid N­ 2. While for high-temperature measurements, the et al. 2010). The aragonite-group carbonates have the space sample pieces were transferred to a Linkam TS1500 heating group symmetry Pmcn (De Villiers 1971). Although up to stage, and high temperatures were achieved by resistance heat- 30 Raman-active vibrational modes are predicted (Couture ing. Raman spectra were collected up to 570 K for cerussite, 1947; Krishnamurti 1960), only 10–13 modes were observed where melting was observed. Aragonite and witherite were in this Raman experiment. The vibrational modes can be heated to 800 and 1150 K, respectively, across the phase tran- ascribed to two groups: lattice vibrations (external modes) −1 sitions, while strontianite persisted up to 1200 K without any (50–350 cm ) and internal vibrations of the CO­ 3 group phase transition. (650–1600 cm−1) (Couture 1947; Krishnamurti 1960; Huang For measurements at low and high temperatures, spec- and Kerr 1960; White 1974; Gillet et al. 1993). Among tra were taken with a temperature interval of 50 K, and the the external vibrational modes, the ones below 200 cm−1 cooling and heating rates were set to be 20 K min−1, as con- are associated with translations of the divalent cation M trolled by an automatic temperature controlling unit. At each (M = Ca, Sr, Pb, Ba), while those above 200 cm−1 are asso- step, the target temperature was maintained for at least 5 min ciated with the rotations and translations of the ­CO3 group to allow thermal equilibrium before measurement, and the (Lin and Liu 1997c). The internal vibrational modes consist −1 uncertainties of temperature were less than 1 K. The Raman of four groups: in-plane bending (ν4, 650–720 cm ), out- −1 −1 frequencies were recorded in the range of 50–1600 cm , of-plane bending (ν2, 840–910 cm ), asymmetric stretch- −1 and a silicon single crystal was used as the reference for ing (ν1, 1000–1100 cm ) and symmetric stretching (ν3, calibrating the spectrometer. 1350–1600 cm−1). The Mid-FTIR spectra (650–2000 cm−1) are also meas- FTIR spectroscopy ured for the carbonates at ambient condition (Fig. S2). The fitted peak positions for the internal modes of theCO ­ 3 group The high-temperature Mid-FTIR spectra of the aragonite- are listed in Table S3, which agree well with the previous group carbonates were obtained using a Nicolet iS50 FTIR IR measurements (Andersen and Brečević 1991 for arag- coupled with a Continuum microscope, which was used to onite; Catalli et al. 2005 for cerussite). Both Raman and record the spectra with a KBr beam-splitter and a MCT-A FITR spectra support the general trend that each of the detector cooled by liquid nitrogen (Yang et al. 2015). To internal modes shifts to lower frequencies in the order of detect the internal C-O bending and stretching modes (in the aragonite > strontianite > witherite > cerussite. range of 650–2000 cm−1) at high temperature, we collected the FTIR spectra in reflection mode. The ground powder Vibrational spectra at temperature (> 2500 mesh) for the carbonate was wiped on a platinum plate and loaded in a Linkam TMS600 heating stage, which Selected Raman and FTIR spectra for the aragonite-group could reach the highest temperature of 873 K. The FTIR carbonates at temperatures are shown in Figs. 1a–d and spectra were collected with a 4 cm−1 resolution and an accu- 2a–d, respectively. For the Raman spectra measured on mulation of 128 scans. The samples of strontianite and with- ­SrCO3 and ­BaCO3, the peaks become weaker and broader, erite were heated from room temperature to 853 K with an and some peaks even overlap severely with each other in increment of 50 K. Aragonite was heated to 773 K, where it the frequency range below 350 cm−1, at temperatures above transformed to calcite; while cerussite was heated to 530 K, 800 K. Hence, it is challenging for peak fitting at higher which is just before melting, at an interval of 40 K. The temperature, and more caution is needed. Since the v1 modes software package Peakfit v4.12 (Sea Solve Software Inc., are typically much stronger than other internal modes in Massachusetts, U.S.A.) was used for the peak fitting for both the Raman spectra, the spectra in Fig. 1a–d are divided Raman and FTIR spectra. into four parts, and each part is rescaled to an appropri- ate intensity individually for clarity: (1) 50–350 cm−1 for −1 the external vibration modes, (2) 650–900 cm for the v4 −1 Results and discussions and v2 modes, (3) 1020–1120 cm for the v1 mode and (4) −1 1300–1600 cm for the v3 mode. Vibrational modes at ambient condition The aragonite–calcite phase transition in CaCO­ 3 was observed at 800 and 773 K, according to the Raman (Fig. 1a) The Raman spectra of aragonite, strontianite, cerussite and FTIR (Fig. 2a) measurements, respectively, while Antao and witherite at ambient conditions are shown in Fig. S1, and Hassan (2010) reported this phase transition in the

1 3 Physics and Chemistry of Minerals

Fig. 1 Selected Raman spectra of the aragonite-group carbonates at (1) 50–350 cm−1 for external vibration modes, (2) 650–900 cm−1 −1 low and high temperatures: a aragonite, b strontianite, c cerussite, d for v4 and v2 modes, (3) 1020–1120 cm for v1 mode and (4) 1300– −1 witherite. Each Raman spectrum is divided into four parts, and each 1600 cm for v3 mode part is rescaled to an appropriate intensity individually for clarity: temperature range of 693–773 K by X-ray powder diffrac- aragonite, which are measured in the Raman and FTIR spec- tion. Upon the phase transition, two new external modes tra from this study, are compared with those from the litera- were clearly observed at 154.6 and 281 cm−1, while the posi- tures in Table S4 (Andersen and Brečević 1991; Andersson tions of the internal v1, v3 and v4 modes also shifted signifi- et al. 2014; Biellmann and Gillet 1992; Brenker et al. 2005; cantly in the Raman spectrum at 800 K. In the FTIR spec- Carteret et al. 2009; Gillet et al. 1993; Gunasekaran et al. trum at 773 K, the two split peaks for the v4 modes merged 2006; Liu and Mernagh 1990; Kraft et al. 1991; Rutt and to one peak at 712.2 cm−1, while the peak at 860.1 cm−1 Nicola 1974; Sánchez-Pastor et al. 2016; Wehrmeister et al. split into two peaks. The calcite phase, which is transformed 2010). from aragonite at high temperature, is quenchable to 300 K, In addition, when BaCO­ 3 was heated to 1150 K, the exter- −1 −1 and another Raman and FTIR spectra for calcite were meas- nal modes below 300 cm and v3 modes above 1300 cm ured when the sample was cooled down (Figs. S1 and S2). could not be clearly distinguished in the Raman spectrum The internal modes of the CO­ 3 group for both calcite and (Fig. 1d), and the v1 and v4 modes shifted significantly

1 3 Physics and Chemistry of Minerals

Fig. 2 Typical FTIR spectra of the aragonite-group carbonates at high temperatures: a aragonite, b strontianite, c cerussite, d witherite

to higher frequency, which is similar to the phenomenon measurement. Hence, the phase transition in BaCO­ 3 is observed in the aragonite–calcite phase transition. Antao reversible in the cooling process. and Hassan (2007) reported a Pmcn-R3m phase transition The variations of the Raman and FTIR modes with tem- in ­BaCO3 around 1084 K by X-ray diffraction, and Nie et al. perature for the aragonite-group carbonates are plotted in (2017) reported the α-BaCO3 phase transformed into a trigo- Figs. 4a–d and 5a–d, respectively. Only the data points meas- nal β-phase at 1073–1093 K also by XRD. Our phase transi- ured before the phase transitions are adopted for linear regres- tion temperature for ­BaCO3 was observed at a little higher sions on aragonite and witherite. The Raman and FTIR spectra temperature (1100–1150 K). However, when the sample was for cerussite are recorded up to 540 K, just below the melting quenched to room temperature, the Raman signals of with- point. Almost all vibrational modes systematically show nega- erite were recovered (Fig. 3). The differences of the Raman tive temperature dependences, except the v4 (in-plane bending) peak positions measured before and after heating are smaller modes, which do not show any significant dependence with than 3 cm−1, which are comparable to the uncertainties of temperature. This phenomenon is consistent with the trends

1 3 Physics and Chemistry of Minerals

 ln vi 1 vi iP = =− (1)  P  ⋅ v0i T P

 ln vi KT vi iT = = (2)  T v0i P T

ln v a i ⋅ i = =− (iP − iT) (3) T V

where νi is the wavenumber of a given vibrational mode, ρ is the density, α is the thermal expansion coefficient, and KT is the isothermal bulk modulus. The isobaric mode Grü- neisen parameters (γiP) of the carbonates are calculated using the temperature dependences of the Raman modes (∂νi/∂T)P obtained in this study and the mean thermal expansion coef- ficient (α0) reported by Ye et al. (2012) (Table 1). Several studies have reported the vibrational modes at high pressure for aragonite (Biellmann and Gillet 1992; Kraft et al. 1991), strontianite (Lin and Liu 1997c), cerus- site (Catalli et al. 2005; Lin and Liu 1997c), and witherite (Chaney et al. 2015; Lin and Liu 1997a). The data points before any phase transition at high pressure were adopted for linear fitting, and the derived (∂νi/∂P)T values are listed in Table S2. Using the recently reported isothermal bulk moduli KT (Table 1), we further calculated the isothermal Grüneisen parameters (γiT) with Eq. (2), which are also Fig. 3 Comparison of Raman spectra for witherite before heating and listed in Table S2 for comparison. quenched from 1150 K The isobaric and isothermal Grüneisen parameters of the external modes (lattice vibration) are plotted as a function of observed in the high-temperature Raman spectra of calcite, frequency in Fig. 6. The γiP parameters of external vibrations magnesite, dolomite and aragonite (Gillet et al. 1993). for cerussite (0.4–1.7) are typically smaller than those for The temperature derivatives of the Raman and IR modes aragonite, strontianite, and witherite (1.2–3.5), except the one −1 (∂vi/∂T)P are listed in Tables S2 and S3, respectively. The at 133.1 cm (Fig. 6a). That is because the reported thermal values of (∂vi/∂T)P typically range from − 0.01 to − 0.03 expansion coefficient for cerussite is significantly higher than ­(cm−1 K−1) for the external modes. For the internal modes those for the other three carbonates (Ye et al. 2012). Never- −1 above 650 cm , both Raman and FTIR experiments show that theless, the γiT parameters for the external vibration modes the magnitudes of (∂vi/∂T)P generally increase with increasing are systematically higher in cerussite (2.1–3.4), compared to frequency, in the order v4 < v2 < v1 < v3. the other aragonite-group carbonates (0.9–1.9). For the internal vibration modes of the CO­ 3 group, the Grüneisen parameters and intrinsic anharmonicity isobaric Grüneisen parameters (γiP) derived from this study and the isothermal Grüneisen parameters (γiT) based on The frequency shift of a given mode (vi) in response to tem- previous studies are shown in Fig. 7. Both the high-tem- perature and pressure arise from two contributions: a pure- perature Raman and FTIR spectra in this study support volume contribution due to compression/thermal expansion the general trend that γiP values increase with increasing (quasi-harmonicity) and a direct contribution of temperature/ frequency for the internal vibrations (Fig. 7a): − 0.06 to pressure arising from intrinsic anharmonicity (Fujimori et al. 0.06 for the in-plane bending modes (v4); 0.06–0.16 for the 2002; Gillet et al. 1989). We separate these two contributions out-of-plane bending modes (v2); 0.10–0.22 for the asym- by calculating the mode Grüneisen parameters and anhar- metric stretching modes (v1); and 0.16–0.40 for the sym- monic parameters. The isobaric mode Grüneisen parameters metric stretching modes (v3). The isothermal Grüneisen γ γ ( iP), isothermal mode Grüneisen parameter ( iT) and intrinsic parameters (γiT) range from − 0.1 to 0.3 for the internal anharmonic mode parameters (ɑi), describing the temperature vibration modes of aragonite-group carbonates. Due to dis- and pressure dependences of the vibrational modes, individu- crepancies among different measurements at high pressure, ally, are defined as: it is hard to conclude any relationship between γiT and vi.

1 3 Physics and Chemistry of Minerals

Fig. 4 Raman shifts as a function of temperature for a aragonite, b strontianite, c cerussite, d witherite. The uncertainties of temperature meas- urements are smaller than the sizes of the symbols

Overall, the lattice vibration modes (below 350 cm−1) contribution to the intrinsic anharmonicity than the internal show systematically larger Grüneisen parameters (γiT and modes. γiP) than those for the stretching modes of the ­CO3 group. The intrinsic anharmonicity (a) plays a key role in the This is consistent with the crystal structure refinements of thermodynamic properties, especially at high temperatures, aragonite at high temperatures and pressures: the M-O bonds for minerals in the mantle (Dorogokupets and Oganov 2004; are more sensitive to the changes of temperature (Antao and Oganov and Dorogokupets 2004). There are 57 zone-cen- Hassan 2010; Ye et al. 2012) and pressure (Li et al. 2015; tered optic modes (including Raman and FTIR) in arago- Palaich et al. 2016), compared with the strong C–O bonds. nite, while the anharmonic parameters were evaluated for The ­CO3 group serves as rigid bodies compared to the ­MO9 less than 10 modes for each carbonate phase, based on the polyhedra, and the CO­ 3 planar layers stack perpendicular to reported Raman datasets at high-temperature or high-pres- the c axis, which yields larger thermal expansivity and com- sure conditions. The calculated external mode parameters pressibility along the c direction (Antao and Hassan 2010; ai for cerussite is systematically higher than those for the Gao et al. 2016; Holl et al. 2000; Li et al. 2015; Martinez other carbonates (Fig. 8), suggesting that the anharmonicity et al. 1996; Palaich et al. 2016; Ross and Reeder 1992; San- for cerussite should be quite different. In addition, cerus- tillán and Williams 2004; Ye et al. 2012). site has a much lower melting point (about 570 K), and the For some of the vibrational modes, both the temperature anharmonic effects could be even more severe at high tem- and pressure dependences are recorded in this study and peratures approaching the melting point. previous experiments, and then we can further calculate the intrinsic anharmonic parameters (ai) based on Eq. (3), Macroscopic Grüneisen parameter which are listed in Table S2 and plotted in Fig. 8. For the and thermodynamics aragonite-group carbonates, the ai values range from − 15 to 11 (10­ −5 K−1) for the external modes (lattice vibration); In the above discussion, the Grüneisen parameters are calcu- and from − 2 to 3 (10­ −5 K−1) for the internal modes of the lated in a microscopic way in the form of a vibrational mode ­CO3 group. Hence, the external modes should have a larger γiT (Grüneisen 1912). The macroscopic Grüneisen parameter,

1 3 Physics and Chemistry of Minerals

Fig. 5 Variations of FTIR mods with temperature for a aragonite, b strontianite, c cerussite, d witherite. The uncertainties of temperature meas- urement are smaller than the sizes of the symbols

Fig. 6 a Isobaric and b isothermal mode Grüneisen parameters as a function of frequency for the external vibrations of the aragonite-group car- bonates. The vertical error bars stand for the uncertainties of calculated Grüneisen parameters, some are smaller than the sizes of the symbols

γ, which is widely used to calculate the adiabatic gradient of Using the parameters listed in Table 1 for thermal expan- the mantle, could be calculated as: sion coefficients (α), adiabatic bulk moduli (KS), heat capac- C ρ  × KS ity ( P) and molar densities ( ), the macroscopic Grüneisen = . parameters at ambient condition were obtained: 1.76(4) for  × CP (4)

1 3 Physics and Chemistry of Minerals

Fig. 7 a Isobaric and b isothermal mode Grüneisen parameters as a neisen parameters, some are smaller than the sizes of the symbols. function of frequency for the internal vibrations of the ­CO3 group. The open and gray symbols in a represent the datasets from Raman The vertical error bars stand for the uncertainties of calculated Grü- and FTIR spectra, respectively

h 3N n 1∕3 ⋅ ⋅  ⋅ V Θac = k 4 M m (5)  where h, k and N are the Boltzmann constant, Plank con- stant and Avogadro’s constant, respectively. M is the molar mass, ρ is densities, and the mean velocity Vm is defined as in Eq. (9): 3 2 1 = + . V3 V3 V3 (6) m S P

With the acoustic velocities (VP and VS) listed in Table 1, the acoustic Debye temperatures are derived: 517(17) K for aragonite; 405(19) K for strontianite; 284(14) K for cerussite; and 339(14) K for witherite. The Debye temperature for cerussite is obviously lower than those for the other three carbonates. Besides, cerussite also has a much lower melting point (570 K) as mentioned Fig. 8 a Intrinsic anharmonic mode parameters ( i) for the aragonite- above. The interatomic bonds in cerussite should be rela- group carbonates. The vertical error bars stand for the uncertainties of tively weaker, and consequently, the thermal expansivity the calculated Grüneisen parameters, some are smaller than the sizes of the symbols and compressibility for cerussite should be higher. This inference is consistent with the high-temperature study by Ye et al. (2012), but in conflict with the high-pressure aragonite, 1.90(6) for strontianite, 2.62(8) for cerussite, and experiment (Gao et al. 2016) and elastic calculation (Bie- γ 1.73(5) for witherite (Table 1). The calculated for cerussite dermann et al. 2017). It should be noted that the adiabatic is significantly larger than those for aragonite, strontianite, and bulk modulus (KS) for cerussite was derived just by theo- witherite, due to the reported larger thermal expansion coeffi- retical simulation. Gao et al. (2016) adopted silicone oil as cient (Ye et al. 2012) and adiabatic bulk modulus for cerussite the pressure medium for high-pressure X-ray diffraction in (Biedermann et al. 2017). To further check such discrepancy, a diamond anvil cell (DAC), and the stress condition could we calculated the acoustic Debye temperatures (Θac) for the be severe inside the DAC chamber at high pressure due aragonite-group carbonates: to such nonhydrostatic compression. Hence, experimental

1 3 Physics and Chemistry of Minerals efforts are still needed for an accurate constraint on the by US National Science Foundation Grant EAR14-16979. Raman elasticity and equation of state for cerussite, especially in spectra were collected at the Center of Physics Experiment Teaching, University of Science and Technology of China, while FTIR spectra a quasi-hydrostatic condition. were obtained at the Micro-FTIR Lab in Department of Earth Sciences, The element Pb belongs to the fourth column in the peri- Institute of Geology and Geophysics, Zhejiang University. Composi- odic table, with the 6s2 lone electron pairs on the ­Pb2+ cation tion analyses by EMPA for aragonite was carried out at the State Key (Siidra et al. 2008), as opposed to the alkaline-earth cations Laboratory of Geological Processes and Mineral Resources, China 2+ 2+ 2+ 2+ University of Geosciences (Wuhan), and we offer many thanks to Dr. of Ca­ , Sr­ and ­Ba . The electronegativity for ­Pb is Simon M. Clark for helpful discussion and Dr. Zhilei Sui and Xiaoyan 2+ 2+ 2.33, which is larger than those for Ca­ (1.00), Sr­ (0.95) Gu for experimental assistance. and ­Ba2+ (0.89) (James and Lord 1992). Larger electronega- tivity could alleviate the interaction between the divalent cation and oxygen anion, and consequently lowers the Debye temperature and melting point. References

Andersen FA, Brečević L (1991) Infrared spectra of amorphous and crystalline calcium carbonate. Acta Chem Scand 45:1018–1024 Conclusions Andersson MP, Hem CP, Schultz LN, Nielsen JW, Pedersen CS, Sand KK, Okhrimenko DV, Johnsson A, Stipp SL (2014) Infrared spec- In situ high-temperature Raman and FTIR spectra were troscopy and density functional theory investigation of calcite, chalk, and coccoliths—do we observe the mineral surface? J Phys measured for the aragonite-group carbonates at ambient Chem A 118:10720–10729 pressure. Both the Raman and FTIR datasets place the arag- Antao SM, Hassan I (2007) BaCO­ 3: high-temperature crystal struc- → onite → calcite phase transition in ­CaCO3 at 773–800 K, and tures and the Pmcn R3m phase transition at 811 °C. Phys Chem the calcite phase was preserved without transforming back to Miner 34:573–580 Antao SM, Hassan I (2009) The orthorhombic structure of ­CaCO , aragonite when cooled down to 300 K, which was confirmed 3 ­SrCO3, ­PbCO3 and ­BaCO3: linear structural trends. Can Mineral by Raman and FTIR measured on the quenched sample. On 47:1245–1255 the other hand, the orthorhombic–triagonal phase transition Antao SM, Hassan I (2010) Temperature dependence of the structural for witherite was observed at 1100–1150 K, and BaCO­ parameters in the transformation of aragonite to calcite, as deter- 3 mined from in situ synchrotron powder X-ray-diffraction data. Can transformed back to witherite when quenched to room tem- Mineral 48:1225–1236 perature according to the Raman measurement. The isobaric Arapan S, Ahuja R (2010) High-pressure phase transformations in car- Grüneisen parameters (γiP) and isothermal Grüneisen param- bonates. Phys Rev B 82:184115 Biedermann N, Winkler B, Speziale S, Reichmann HJ, Koch-Müller eters (γiT) range from 0.9 to 3.5 for the lattice vibrational −1 M (2017) Single-crystal elasticity of ­SrCO3 by Brillouin spectros- modes (below 350 cm ), which are systematically higher copy. High Press Res 37:181–192 than those for the internal modes (< 0.4) of the ­CO3 group Biellmann C, Gillet P (1992) High-pressure and high-temperature (650–1600 cm−1). Both the Raman and FTIR spectra in behaviour of calcite, aragonite and dolomite: a Raman spectro- scopic study. Eur J Mineral 4:389–393 this study indicate that the internal mode parameters (γiP) v Bissengaliyeva MR, Gogol DB, Taimassova ST, Bekturganov NS vary in the order of: in-plane bending modes ( 4) < out-of- (2012) The heat capacity and thermodynamic functions of cerus- plane bending modes (v2) < symmetric stretching modes site. J Chem Thermodyn 47:197–202 (v1) < asymmetric stretching modes (v3). The in-plane bend- Brenker F, Vincze L, Vekemans B, Nasdala L, Stachel T, Vollmer C, ing modes are almost insensitive to temperature changes. Kersten M, Somogyi A, Adams F, Joswig W (2005) Detection a of a Ca-rich lithology in the Earth’s deep (> 300 km) convecting The intrinsic anharmonic parameters ( i) were evalu- mantle. Earth Planet Sci Lett 236:579–587 ated for some of the vibrational modes, and cerussite shows Carteret C, Dandeu A, Moussaoui S, Muhr H, Humbert B, Plasari larger positive ai parameters for the external modes (below E (2009) Polymorphism studied by lattice phonon Raman spec- 350 cm−1), compared with those for the other aragonite- troscopy and statistical mixture analysis method. Application to calcium carbonate polymorphs during batch crystallization. Cryst group carbonates. In addition, cerussite has a significantly Growth Des 9:807–812 lower Debye temperature and melting point, implying that its Caspi E, Pokroy B, Lee P, Quintana J, Zolotoyabko E (2005) On the thermal expansivity and compressibility should be relatively structure of aragonite. Acta Crystallogr B16:129–132 higher. Further experiments at simultaneously high tempera- Catalli K, Santillán J, Williams Q (2005) A high pressure infrared spec- troscopic study of ­PbCO3-cerussite: constraints on the structure of ture and high pressure are still needed for more accurate the post-aragonite phase. Phys Chem Miner 32:412–417 constraints on the anharmonic effects on equation of states Chaney J, Santillán JD, Knittle E, Williams Q (2015) A high-pressure and thermodynamics, which is important for understanding infrared and Raman spectroscopic study of ­BaCO3: the aragonite, the physical behavior of carbonates in the deep Earth. trigonal and Pmmn structures. Phys Chem Miner 42:83–93 Couture L (1947) Etude des spectres de vibrations de monocristaux ioniques. Ann Phys N Y 12:5–94 Acknowledgements YY acknowledge support from the National Key Dasgupta R, Hirschmann MM (2010) The deep carbon cycle and melt- R&D Program of China (no. 2016YFC0600204) and the National Nat- ing in Earth’s interior. Earth Planet Sci Lett 298:1–13 ural Science Foundation of China (no. 41672041). JRS was supported

1 3 Physics and Chemistry of Minerals

De Villiers RJP (1971) The crystal structures of aragonite, strontianite, Liu Q, Jin ZM, Zhang JF (2009) An experimental study of dehydration and witherite. Am Mineral 56:758–767 melting of phengite-bearing eclogite at 1.5–3.0 GPa. Chin Sci Dorogokupets PI, Oganov AR (2004) Intrinsic anharmonicity in equa- Bull 54:1455–1464 tions of state of solids and minerals. Dokl Earth Sci 395:238–241 Lobanov SS, Dong X, Martirosyan NS, Samtsevich AI, Stevanovic Fujimori H, Komatsu H, Ioku K, Goto S, Yoshimura M (2002) Anhar- V, Gavryushkin PN, Litasov KD, Greenberg E, Prakapenka VB, monic lattice mode of Ca­ 2SiO4: ultraviolet laser Raman spectros- Oganov AR, Goncharov AF (2017) Raman spectroscopy and 3 copy at high temperatures. Phys Rev B 66:064306 X-ray diffraction of sp CaCO­ 3 at lower mantle pressures. Phys Gao J, Wu X, Qin S, Li YC (2016) Pressure-induced phase transfor- Rev B 96:104101 mations of PbCO­ 3 by X-ray diffraction and Raman spectroscopy. Marcondes ML, Justo JF, Assali LVC (2016) Carbonates at high pres- High Press Res 36:1–15 sures: possible carriers for deep carbon reservoirs in the Earth’s Gillet P, Guyot F, Malezieux J-M (1989) High-pressure, high-tem- lower mantle. Phys Rev B 94:104112 perature Raman spectroscopy of ­Ca2GeO4 (olivine form): some Martens WN, Rintoul L, Kloprogge JT, Frost RL (2004) Single crystal insights on anharmonicity. Phys Earth Planet Inter 58:141–154 Raman spectroscopy of cerussite. Am Mineral 89:352–358 Gillet P, Biellmann C, Reynard B, McMillan P (1993) Raman spectro- Martinez I, Zhang J, Reeder RJ (1996) In situ X-ray diffraction of scopic studies of carbonates part I: high-pressure and high-tem- aragonite and dolomite at high pressure and high temperature: perature behaviour of calcite, magnesite, dolomite and aragonite. evidence for dolomite breakdown to aragonite and magnesite. Am Phys Chem Miner 20:1–18 Mineral 81:611–624 Grüneisen E (1912) Theorie des festen Zustandes einatomiger Ele- Minch R, Dubrovinsky L, Kurnosov A, Ehm L, Knorr K, Depmeier W mente. Ann Phys Berl 344:257–306 (2010a) Raman spectroscopic study of ­PbCO3 at high pressures Gunasekaran S, Anbalagan G, Pandi S (2006) Raman and infrared and temperatures. Phys Chem Miner 37:45–56 spectra of carbonates of calcite structure. J Raman Spectrosc Minch R, Peters L, Ehm L, Knorr K, Siidra OI, Prakapenka V, Dera P, 37:892–899 Depmeier W (2010b) Evidence for the existence of a ­PbCO3-II Gurevich VM, Gavrichev KS, Gorbunov VE, Danilova TV, Golushina phase from high pressure X-ray measurements. Z Kristallogr LN (2001a) Low-temperature heat capacity of strontianite 225:146–152 ­SrCO3(c). Geochem Int 39:676–682 Nie S, Liu Y, Liu Q, Wang M, Wang H (2017) Phase transitions and Gurevich VM, Gavrichev KS, Gorbunov VE, Danilova TV, Golushina thermal expansion of ­BaCO3 and ­SrCO3 up to 1413 K. Eur J Min- LN, Khodakovskii IL (2001b) Low-temperature heat capacity of eral 29:433–443 witherite ­BaCO3(c). Geochem Int 39:1007–1014 Oganov AR, Dorogokupets PI (2004) Intrinsic anharmonicity in equa- Holl CM, Smyth JR, Laustsen HMS, Jacobsen SD, Downs RT (2000) tions of state and thermodynamics of solids. J Phys Condens Mat Compression of witherite to 8 Gpa and the crystal structure of 16:1351–1360 ­BaCO3 II. Phys Chem Miner 27:467–473 Oganov AR, Glass CW, Ono S (2006) High-pressure phases of ­CaCO3: Huang CK, Kerr PF (1960) Infrared study of carbonate minerals. Am crystal structure prediction and experiment. Earth Planet Sci Lett Mineral 45:311–324 241:95–103 James AM, Lord MP (1992) MacMillan’s chemical and physical data. Ono S (2005) Post-aragonite phase transformation in ­CaCO3 at 40 GPa. Macmillan Press, Basingstoke Am Mineral 90:667–671 Keppler H, Wiedenbeck M, Shcheka SS (2003) Carbon solubility in Ono S, Kikegawa T, Ohishi Y (2007) High-pressure transition of olivine and the mode of carbon storage in the Earth’s mantle. ­CaCO3. Am Mineral 92:1246–1249 Nature 424:414–416 Palaich SEM, Heffern RA, Hanfland M, Lausi A, Kavner A, Manning Kraft S, Knittle E, Williams Q (1991) Carbonate stability in the CE, Merlini M (2016) High-pressure compressibility and thermal Earth’s mantle: a vibrational spectroscopic study of aragonite expansion of aragonite. Am Mineral 101:1651–1658 and dolomite at high pressures and temperatures. J Geophys Res Pokroy B, Fieramosca J, Von Breele R, Fitch A, Caspi E, Zolotoyabko 96:17997–18009 E (2007) Atomic structure of biogenic aragonite. Chem Mater Krishnamurti D (1960) The Raman spectra of aragonite, strontianite 19:3244–3251 and witherite. Proc Natl Acad Sci India A 51:285–295 Ross NL, Reeder RJ (1992) High-pressure structural study of dolomite Li Y, Zou Y, Chen T, Wang X, Qi X, Chen H, Du J, Li B (2015) P-V-T and ankerite. Am Mineral 77:412–421 equation of state and high-pressure behavior of CaCO­ 3 aragonite. Rutt HN, Nicola JH (1974) Raman spectra of carbonates of calcite Am Mineral 100:2323–2329 structure. J Phys C Solis State Phys 7:4522–4528 Lin CC, Liu JG (1997a) High-pressure Raman spectroscopic study of Sánchez-Pastor N, Oehlerich M, Astilleros JM, Kaliwoda M, Mayr post-aragonite phase transition in witherite ­(BaCO3). Eur J Min- CC, Fernández-Díaz L, Schmahl WW (2016) Crystallization of eral 9:785–792 ikaite and its pseudomorphic transformation into calcite: Raman Lin CC, Liu JG (1997b) High pressure phase transformations in arag- spectroscopy evidence. Geochim Cosmochim Acta 175:271–281 onite-type carbonates. Phys Chem Miner 24:149–157 Sanchez-Valle C, Ghosh S, Rosa A (2011) Sound velocities of fer- Lin CC, Liu LG (1997c) Post-aragonite phase transitions in strontianite romagnesian carbonates and seismic detection of carbonates in and cerussite—a high-pressure Raman spectroscopic study. J Phys eclogites and the mantle. Geophys Res Lett 38:L24315 Chem Solids 58:977–987 Santillán J, Williams Q (2004) A high pressure X-ray diffraction study Litasov KD, Shatskiy A, Gavryushkin PN, Bekhtenova AE, Dorogoku- of aragonite and the post-aragonite phase transition in ­CaCO3. Am pets PI, Danilov BS, Higo Y, Akilbekov AT, Inerbaev TM (2017) Mineral 89:1348–1352 P-V-T equation of state of ­CaCO3 aragonite to 29 GPa and 1673 K: Siidra OI, Krivovichev SV, Filatov SK (2008) Minerals and synthetic in situ X-ray diffraction study. Phys Earth Planet Inter 265:82–91 Pb(II) compounds with oxocentered tetrahedra: review and clas- Liu LG, Mernagh TP (1990) Phase transitions and Raman spectra sification. Z Kristallogr-Cryst Mat 223:114–125 of calcite at high pressures and room temperature. Am Mineral Smith D, Lawler KV, Martinez-Canales M, Daykin AW, Fussell Z, 75:801–806 Smith GA, Childs C, Smith JS, Pickard CJ, Salamat A (2018) Liu LG, Chen CC, Lin CC (2005) Elasticity of single-crystal aragonite Postaragonite phases of ­CaCO3 at lower mantle pressures. Phys by Brillouin spectroscopy. Phys Chem Miner 32:97–102 Rev Materials 2:013605 Speer JA (1983) Crystal chemistry and phase relations of orthorhombic carbonates. Rev Mineral Geochem 11:145–190

1 3 Physics and Chemistry of Minerals

Sui Z, Wu J, Wang X, Dai R, Wang Z, Zheng X, Zhang Z (2016) Cyclic biological vaterite: a Raman spectroscopic study. J Raman Spec- phase transition from hexagonal to orthorhombic then back to trosc 41:193–201 hexagonal of EuF­ 3 while loading uniaxial pressure and under high White WB (1974) The carbonate minerals. In: Farmer VC (ed) The temperature. J Phys Chem C 120:18780–18787 infrared spectra of minerals. Mineralogical Society of Great Brit- Suito K, Namba J, Horikawa T, Taniguchi y, SakuRai N, Kobayashi ain and Ireland, London, pp 227–284 M, Onodera A, Shimomura O, Kikegawa T (2001) Phase relations Yang Y, Wang Z, Smyth JR, Liu J, Xia Q (2015) Water effects on the of ­CaCO3 at high pressure and high temperature. Am Mineral anharmonic properties of forsterite. Am Mineral 100:2185–2190 86:997–1002 Ye Y, Smyth JR, Boni P (2012) Crystal structure and thermal expansion Ungureanu CG, Prencipe M, Cossio R (2010) Ab initio quantum- of aragonite-group carbonates by single-crystal X-ray diffraction. mechanical calculation of CaCO­ 3 aragonite at high pressure: ther- Am Mineral 97:707–712 modynamic properties and comparison with experimental data. Zhang YF, Liu J, Qin ZX, Lin CL, Xiong L, Li R, Bai LG (2013) A Eur J Mineral 22:693–701 high-pressure study of PbCO3 by XRD and Raman spectroscopy. Wang M, Liu Q, Nie S, Li B, Wu Y, Gao J, Wei X, Wu X (2015) Chin Phys C 37:038001 High-pressure phase transitions and compressibilities of arago- Zhang X, Yang SY, Zhao H, Jiang SY, Zhang RX, Xie J (2017) Effect nite-structure carbonates: SrCO­ 3 and ­BaCO3. Phys Chem Miner of beam current and diameter on electron probe microanalysis 42:517–527 of carbonate minerals. J Earth Sci. https​://doi.org/10.1007/s1258​ Wehrmeister U, Soldati AL, Jacob DE, Häger T, Hofmeister W 3-017-0939-x (2010) Raman spectroscopy of synthetic, geological and

1 3