Raman Evidences of Chemical Reaction of NaCl-O2 System at High Pressure and High Temperature
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摘要: 利用金刚石压腔装置和显微激光双面加热技术，对NaCl-O2体系在高温高压下的化学反应进行研究。在55 GPa下对样品进行激光加热，使温度达到1 500~2 000 K，然后在常温下对产物进行拉曼光谱测量。测试数据显示，NaCl-O2体系在上述温压条件下发生了化学反应，产物包括NaO4、NaCl3等非传统化合物，以及少量的NaClO4和中间产物Cl2。易吸潮的NaO4黑色粉末在常压下仍稳定存在，其1 384 cm-1特征振动峰反映其结构中存在带分数负电荷的O-O原子对。斜方结构NaCl3表现出强的拉曼信号，可分辨出10个拉曼峰，并在卸压过程中于23 GPa左右完全分解为NaCl+Cl2。实验结果表明，高压有利于O元素和Cl元素以非常规阴离子对或聚阴离子的形式出现，并表现出异于常压和较低压时的化学反应特性。这些特性是否具有普遍性还需要更多的实验体系证实。研究结果为探讨地幔深处氧可能的非常规存在方式提供了新的证据。Abstract: In this study we studied the chemical reaction of the NaCl-O2 system under high pressure and high temperature using the diamond anvil cell apparatus and the double-sided laser heating technology.The sample was heated to about 1 500-2 000 K under a pressure of 55 GPa, and then analyzed by the Raman measurement at room temperature.The determined data show that the NaCl-O2 system undergoes a chemical reaction under the above-mentioned pressure and temperature conditions.The products include the nontraditional compounds of NaO4 and NaCl3, as well as a small amount of NaClO4 and intermediate product Cl2.The black NaO4 powder, being apt to absorb moisture, can still exist in the ambient condition.The diagnostic zero-pressure Raman band of 1 384 cm-1, assigned to the symmetric stretching vibration of the O4- anion in NaO4, suggests the occurrence of O-O atom pair with a negative fractional valence in the structure.The orthorhombic structure of NaCl3 exhibited a strong Raman signal, which could distinguish 10 Raman peaks in our measurements.It decomposes into NaCl+Cl2 under about 23 GPa on decompression.The experimental results suggest that both elements of oxygen and chlorine prefer to occur in the unconventional form of pair-anions or polyanions caused by their unique chemical reactivity under high pressure, differing from that in atmospheric and lower pressure environments.It requires more robust evidences from various experimental systems to confirm whether these properties of oxygen and chlorine under high pressure are universal.Oxygen is one of the most important constituent elements on Earth, and most of the Earth is in high temperature and high pressure environment.This study provides new evidence for the possible unconventional existence of oxygen in the mantle.
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Key words:
- NaCl-O2 system /
- high pressure and high temperature /
- Raman spectrum /
- NaO4 /
- NaCl3
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图 1 NaCl-O2体系高温高压化学反应前后代表性拉曼光谱
(曲线a为加热前测量结果(55.1 GPa)，反映ε-O2的信号；曲线b和曲线c(53.5 GPa)代表加热后不同测量点的拉曼光谱，曲线d为57 GPa时斜方结构(Pnma)NaCl3的拉曼光谱[12]，与曲线c对照)
Figure 1. Representative high pressure Raman spectra of experimental NaCl-O2 system obtained before and after high temperature and high pressure chemical reaction
(The curve a (55.1 GPa) presents the observed result of the sample before heating, which is the Raman signal of ε-O2 under this pressure; both curve b and curve c (53.5 GPa) present the Raman spectra measured at various positions after heating; curve d, cited from Ref.[12] for comparison with the 53.5 GPa curve c, is the Raman spectrum of the orthorhombic (Pnma) NaCl3 at 57 GPa.)
图 2 常压下NaO4黑色粉末的1 384 cm-1特征拉曼峰
Figure 2. Characteristic 1 384 cm-1 Raman band of the black NaO4 powder sample in ambient conditions
图 3 卸压过程中测量的固体Cmca-Cl2的拉曼光谱(6.9 GPa时)和NaClO4的拉曼光谱(0.1 MPa)
Figure 3. Observed Raman spectra of solid Cmca-Cl2 under 6.9 GPa and NaClO4 under 0.1 MPa in decompression
表 1 53.5 GPa压力下实验观测的斜方结构NaCl3(Pnma)拉曼谱带频率
Table 1. Raman modes of the orthorhombic NaCl3 (Pnma) observed at 53.5 GPa
(cm-1) ν1 ν2 ν3 ν4 ν5 ν6 ν7 ν8 ν9 ν10 204 218 246 284 305 336 388 408 428 480 
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[1] HU Q, KIM D Y, YANG W, et al.FeO2 and FeOOH under deep lower-mantle conditions and Earth's oxygen-hydrogen cycles[J]. Nature, 2016, 534(7606):241-244. doi: 10.1038/nature18018 [2] FREIMAN Y A, JODL H J.Solid oxygen[J]. Phy Rep, 2004, 401(1):1-228. http://d.old.wanfangdata.com.cn/Periodical/jsxb200605011 [3] BORISOV A, PALME H.Experimental determination of the solubility of platinum in silicate melts[J]. Geochimica et Cosmochimica Acta, 1997, 61(20):4349-4357. doi: 10.1016/S0016-7037(97)00268-8 [4] FROST D J, LIEBSKE C, LANGENHORST F, et al.Experimental evidence for the existence of iron-rich metal in the Earth's lower mantle[J]. Nature, 2004, 428(6981):409-412. doi: 10.1038/nature02413 [5] KAWASAKI S, TAKANO M, KANNO R, et al.Phase transitions in Fe4+ (3d4)-perovskite oxides dominated by oxygen-hole character[J]. J Phys Soc Jpn, 1998, 67(5):1529-1532. doi: 10.1143/JPSJ.67.1529 [6] KOHSAKA Y, AZUMA M, YAMADA I, et al.Growth of Na-doped Ca2CuO2Cl2 single crystals under high pressures of several GPa[J]. J Am Chem Soc, 2002, 124(41):12275-12278. doi: 10.1021/ja026680i [7] AZUMA M, SAITO T, ISHIWATA S, et al.Single crystal growth of transition metal oxides at high pressures of several GPa[J]. Physica C, 2003, 392:22-28. http://cpfd.cnki.com.cn/Article/CPFDTOTAL-ZGWJ200107001239.htm [8] CHENG J G, ZHOU J S, GOODENOUGH J B, et al.Pressure dependence of metal-insulator transition in perovskites RNiO3 (R=Eu, Y, Lu)[J]. Phys Rev B, 2010, 82(8):085107. doi: 10.1103/PhysRevB.82.085107 [9] WALKER D, CLARK S M, CRANSWICK L M D, et al.O2 volumes at high pressure from KClO4 decomposition:D″ as a siderophile element pump instead of a lid on the core[J]. Geochem Geophys Geosystems, 2002, 3(11):1-26. doi: 10.1029/2001GC000225/full [10] MAO H K, XU J A, BELL P M.Calibration of the ruby pressure gauge to 800 kbar under quasi-hydrostatic conditions[J]. J Geophys Res Solid Earth, 1986, 91(B5):4673-4676. doi: 10.1029/JB091iB05p04673 [11] ONO S, MIBE K, OHISHI Y.Raman spectra of culet face of diamond anvils and application as optical pressure sensor to high temperatures[J]. J Appl Phys, 2014, 116(5):053517. doi: 10.1063/1.4891681 [12] ZHANG W, OGANOV A R, GONCHAROV A F, et al.Unexpected stable stoichiometries of sodium chlorides[J]. Science, 2013, 342(6165):1502-1505. doi: 10.1126/science.1244989 [13] AKAHAMA Y, KAWAMURA H.High-pressure Raman spectroscopy of solid oxygen[J]. Phys Rev B, 1996, 54(22):R15602. doi: 10.1103/PhysRevB.54.R15602 [14] JOHANNSEN P G, HOLZAPFEL W B.Effect of pressure on Raman spectra of solid chlorine[J]. J Phys C, 1983, 16(33):L1177. doi: 10.1088/0022-3719/16/33/001 [15] BOEHLER R, ROSS M, BOERCKER D B.Melting of LiF and NaCl to 1 Mbar:systematics of ionic solids at extreme conditions[J]. Phys Rev Lett, 1997, 78(24):4589-4592. doi: 10.1103/PhysRevLett.78.4589 [16] HARTMANN P, BENDER C L, VRACAR M, et al.A rechargeable room-temperature sodium superoxide (NaO2) battery[J]. Nat Mater, 2013, 12(3):228-232. doi: 10.1038/nmat3486 [17] BATES J B, BROOKER M H, BOYD G E.Raman spectra of O2- and O3- ions in alkali-metal superoxides and ozonides[J]. Chem Phys Lett, 1972, 16(2):391-395. doi: 10.1016/0009-2614(72)80300-2 [18] MANCERON L, LE QUERE A M, PERCHARD J P.Reinvestigation of the infrared spectrum of the tetroxide anion in solid argon:structural implications[J]. J Phys Chem, 1989, 93(8):2960-2963. doi: 10.1021/j100345a022 [19] CHERTIHIN G V, ANDREWS L.On the spectrum and structure of the isolated O4- anion in solid argon[J]. J Chem Phys, 1998, 108(15):6404-6407. doi: 10.1063/1.476047 [20] AQUINO A J A, TAYLOR P R, WALCH S P.Structure, properties, and photodissociation of O4-[J]. J Chem Phys, 2001, 114(7):3010-3017. doi: 10.1063/1.1288379 [21] DONG X, LI Y L, OGANOV A R, et al.Novel chemistry of lithium oxides and superconducting low-pressure LiO4[EB/OL].[2017-06-02]. https://arxiv.org/abs/1603.02880. [22] BRÜCKNER R, HALLER H, ELLWANGER M, et al.Polychloride monoanions from [Cl3]- to [Cl9]-:a Raman spectroscopic and quantum chemical investigation[J]. Chem-Eur J, 2012, 18(18):5741-5747. doi: 10.1002/chem.v18.18 [23] TOUPRY-KRAUZMAN N, POULET H.Temperature dependence of the Raman spectra of NaClO4 in relation to the 581 K phase transition[J]. J Raman Spectrosc, 1978, 7(1):1-6. doi: 10.1002/jrs.1250070105/full [24] LUTZ H D, BECKER R A, KRUSKA B G, et al.Raman-, IR- und FIR-messungen an wasserfreiem natriumperchlorat NaClO4 im temperaturbereich zwischen 90 und 600 K[J]. Spectrochim Acta Part A, 1979, 35(7):797-806. doi: 10.1016/0584-8539(79)80037-9 [25] EYSEL H H.Raman intensities of liquids:absolute scattering activities and Cl-O bond EOPs of ClO-, ClO2-, ClO3- and ClO4- ions in aqueous solution[J]. Spectrochim Acta Part A, 1988, 44(10):991-997. doi: 10.1016/0584-8539(88)80218-6 -
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