Thermal behavior of [Ca(H2O)4](ClO4)2 and [Ca(NH3)6](ClO4)2

Migdał-Mikuli, Anna; Hetmańczyk, Joanna

doi:10.1007/s10973-007-8511-z

Cited by 31 publications

(18 citation statements)

References 8 publications

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“…We 6 ]X 2 (where X = Cl, Br) involving deammination is similar to our results [7,23,24]. At the higher temperatures the perchlorates explodes and CaCl 2 and BaCl 2 are formed as a final product of decomposition.…”

Section: Resultssupporting

confidence: 87%

Comparison of vibrational dynamics, thermal behaviour, and phase transition in [Ni(NH3)4](ReO4)2 and [Ni(NH3)6](ReO4)2

Hetmańczyk

2014

J Therm Anal Calorim

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The differences between thermal and vibrational properties of [Ni(NH 3 ) 4 ](ReO 4 ) 2 and [Ni(NH 3 ) 6 ] (ReO 4 ) 2 are reported. The differential scanning calorimetry revealed that tetraamminenickel(II) perrhenate exhibits, in the temperature range of 300-140 K, one phase transition at ca. T c h = 188 K (on heating) and T c c = 185 K (on cooling). In the case of hexaamminenickel(II) perrhenate, no phase transition was observed in the same temperature region. Thermogravimetric measurements showed that the decomposition proceeds in the two main stages. In the first stage, a complete deammination takes place and next Re 2 O 7 is released. TG measurements showed that NH 3 molecules are not equivalently bonded to central atom. The final and intermediate products of decomposition were analysed by means of infrared spectroscopy. The final product of thermal decomposition of both compounds is nickel(II) oxide. The analysis of far infrared spectra revealed that anions in [Ni(NH 3 ) 6 ](ReO 4 ) 2 have disturbed tetrahedral symmetry, whereas in [Ni(NH 3 ) 4 ](ReO 4 ) 2 they seem to form polymeric chains. The variation of the activation energies of the deammination and decomposition steps of [Ni(NH 3 ) 6 ](ReO 4 ) 2 was calculated through the model-free isoconversional Kissinger-Akahira-Sunose method and model-free Kissinger method. Infrared spectra were calculated by the DFT method and quite a good agreement with the experimental data was obtained.

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Section: Resultssupporting

confidence: 87%

Comparison of vibrational dynamics, thermal behaviour, and phase transition in [Ni(NH3)4](ReO4)2 and [Ni(NH3)6](ReO4)2

Hetmańczyk

2014

J Therm Anal Calorim

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“…The details of the thermal decomposition of calcium and magnesium perchlorate as a function of temperature and pressure have been described previously [ Acheson and Jacobs , ; Cannon et al ., ; Devlin and Herley , ; Migdal‐Mikuli and Hetmanczyk , ]. The decomposition of these perchlorate salts proceeds in multiple stages with dehydration at temperatures below 375°C, followed by decomposition of the anhydrous salt at temperatures above 400°C [ Acheson and Jacobs , ; Cannon et al ., ; Migdal‐Mikuli and Hetmanczyk , ]. The actual decomposition temperatures of these perchlorates in Rocknest are lower compared to most laboratory experiments since SAM pyrolysis was conducted at a lower pressure of ~25 mbar and other phases in Rocknest could lower the decomposition temperatures of these perchlorates.…”

Section: Sam Resultsmentioning

confidence: 99%

“…These perchlorates may contain a significant amount of water under Martian conditions as they are extremely deliquescent and can form eutectic brines down to temperatures as low as −34 to −74°C [ Marion et al ., ; Robertson and Bish , ]. Although calcium perchlorate does not produce significant amounts of HCl or Cl 2 during decomposition [ Migdal‐Mikuli and Hetmanczyk , ], formation of some HCl from the reaction of CaCl 2 with H 2 O at elevated temperatures is possible (e.g., Figure a; Cannon et al . []).…”

Section: Sam Resultsmentioning

confidence: 99%

Evidence for perchlorates and the origin of chlorinated hydrocarbons detected by SAM at the Rocknest aeolian deposit in Gale Crater

et al. 2013

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[1] A single scoop of the Rocknest aeolian deposit was sieved (< 150 μm), and four separate sample portions, each with a mass of~50 mg, were delivered to individual cups inside the Sample Analysis at Mars (SAM) instrument by the Mars Science Laboratory rover's sample acquisition system. The samples were analyzed separately by the SAM pyrolysis evolved gas and gas chromatograph mass spectrometer analysis modes. Several chlorinated hydrocarbons including chloromethane, dichloromethane, trichloromethane, a chloromethylpropene, and chlorobenzene were identified by SAM above background levels with abundances of~0.01 to 2.3 nmol. The evolution of the chloromethanes observed during pyrolysis is coincident with the increase in O 2 released from the Rocknest sample and the decomposition of a product of N-methyl-N-(tert-butyldimethylsilyl)-trifluoroacetamide (MTBSTFA), a chemical whose vapors were released from a derivatization cup inside SAM. The best candidate for the oxychlorine compounds in Rocknest is a hydrated calcium perchlorate (Ca(ClO 4 ) 2 ·nH 2 O), based on the temperature release of O 2 that correlates with the release of the chlorinated hydrocarbons measured by SAM, although other chlorine-bearing phases are being considered. Laboratory analog experiments suggest that the reaction of Martian chlorine from perchlorate decomposition with terrestrial organic carbon from MTBSTFA during pyrolysis can explain the presence of three chloromethanes and a chloromethylpropene detected by SAM. Chlorobenzene may be attributed to reactions of Martian chlorine released during pyrolysis with terrestrial benzene or toluene derived from 2,6-diphenylphenylene oxide (Tenax) on the SAM hydrocarbon trap. At this time we do not have definitive evidence to support a nonterrestrial carbon source for these chlorinated hydrocarbons, nor do we exclude the possibility that future SAM analyses will reveal the presence of organic compounds native to the Martian regolith.Citation: Glavin, D. P., et al. (2013), Evidence for perchlorates and the origin of chlorinated hydrocarbons detected by SAM at the Rocknest aeolian deposit in Gale Crater,

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“…Only the Fe and Mg oxychlorine species chlorate and perchlorate are known to release HCl. All other oxychlorine phases typically form corresponding chloride phases (e.g., CaCl 2 , NaCl, and KCl) with no significant HCl evolution [e.g., Marvin and Woolaver, 1945;Markowitz, 1963;Migdal-Mikuli and Hetmańczyk, 2008;Cannon et al, 2012]. The temperature of O 2 and HCl evolution was likely too high to be Fe perchlorate or Fe chlorate [e.g., Glavin et al, 2013].…”

Section: Hydrochloric Acid (Hcl)mentioning

confidence: 99%

Evolved gas analyses of sedimentary rocks and eolian sediment in Gale Crater, Mars: Results of the Curiosity rover's sample analysis at Mars instrument from Yellowknife Bay to the Namib Dune

et al. 2017

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The sample analysis at Mars instrument evolved gas analyzer (SAM-EGA) has detected evolved water, H 2 , SO 2 , H 2 S, NO, CO 2 , CO, O 2 , and HCl from two eolian sediments and nine sedimentary rocks from Gale Crater, Mars. These evolved gas detections indicate nitrates, organics, oxychlorine phase, and sulfates are widespread with phyllosilicates and carbonates occurring in select Gale Crater materials. Coevolved CO 2 (160 ± 248-2373 ± 820 μgC (CO2) /g) and CO (11 ± 3-320 ± 130 μgC (CO) /g) suggest that organic C is present in Gale Crater materials. Five samples evolved CO 2 at temperatures consistent with carbonate (0.32 ± 0.05-0.70 ± 0.1 wt % CO 3 ). Evolved NO amounts to 0.002 ± 0.007-0.06 ± 0.03 wt % NO 3 . Evolution of O 2 suggests that oxychlorine phases (chlorate/perchlorate) (0.05 ± 0.025-1.05 ± 0.44 wt % ClO 4 ) are present, while SO 2 evolution indicates the presence of crystalline and/or poorly crystalline Fe and Mg sulfate and possibly sulfide. Evolved H 2 O (0.9 ± 0.3-2.5 ± 1.6 wt % H 2 O) is consistent with the presence of adsorbed water, hydrated salts, interlayer/structural water from phyllosilicates, and possible inclusion water in mineral/amorphous phases. Evolved H 2 and H 2 S suggest that reduced phases occur despite the presence of oxidized phases (nitrate, oxychlorine, sulfate, and carbonate). SAM results coupled with CheMin mineralogical and Alpha-Particle X-ray Spectrometer elemental analyses indicate that Gale Crater sedimentary rocks have experienced a complex authigenetic/diagenetic history involving fluids with varying pH, redox, and salt composition. The inferred geochemical conditions were favorable for microbial habitability and if life ever existed, there was likely sufficient organic C to support a small microbial population.

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Thermal behavior of [Ca(H2O)4](ClO4)2 and [Ca(NH3)6](ClO4)2

Cited by 31 publications

References 8 publications

Comparison of vibrational dynamics, thermal behaviour, and phase transition in [Ni(NH3)4](ReO4)2 and [Ni(NH3)6](ReO4)2

Comparison of vibrational dynamics, thermal behaviour, and phase transition in [Ni(NH3)4](ReO4)2 and [Ni(NH3)6](ReO4)2

Evidence for perchlorates and the origin of chlorinated hydrocarbons detected by SAM at the Rocknest aeolian deposit in Gale Crater

Evolved gas analyses of sedimentary rocks and eolian sediment in Gale Crater, Mars: Results of the Curiosity rover's sample analysis at Mars instrument from Yellowknife Bay to the Namib Dune

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