H2O Phase Research Articles

Influence of the reaction time on the physical–chemical and catalytic properties of vanadium phosphate catalysts prepared by a eutectic mixture

Vanadium phosphate (VPO) materials with high specific surface area prepared via a eutectic mixture as solvent and template with different lengths of time, i.e. 24, 72 and 144 h, were investigated in the oxidation of benzyl alcohol. The X-ray diffraction result indicated the initial VPO precursor was an amorphous phase due to the stronger incorporation of eutectic mixture. On subsequent reflux duration of 72 h, the precursor was composed of a crystallised VOHPO 4 ·H 2 O phase. On further reflux duration of 144 h, the incorporated eutectic mixture gradually was leached out and the precursor became more crystalline. Interestingly the N 2 adsorption–desorption measurements Brunauer–Emmett–Teller studies showed that the VPO precursor incorporated eutectic mixture was mesostructured and the specific surface area first increased then decreased with increasing the reflux duration time. The growth process of the VPO nanostructures formed in a eutectic mixture with different lengths of time was investigated by scanning electron microscopic analysis. The influence of calcination temperature and lengths of reflux duration on the activity and selectivity of the VPO catalyst was studied and discussed.

Crystal Chemistry and High-Temperature Behaviour of Ammonium Phases NH4MgCl3·6H2O and (NH4)2Fe3+Cl5·H2O from the Burned Dumps of the Chelyabinsk Coal Basin

The technogenic mineral phases NH4MgCl3·6H2O and (NH4)2Fe3+Cl5·H2O from the burned dumps of the Chelyabinsk coal basin have been investigated by single-crystal X-ray diffraction, scanning electron microscopy and high-temperature powder X-ray diffraction. The NH4MgCl3·6H2O phase is monoclinic, space group C2/c, unit cell parameters a = 9.3091(9), b = 9.5353(7), c = 13.2941(12) Å, β = 90.089(8)° and V = 1180.05(18) Å3. The crystal structure of NH4MgCl3·6H2O was refined to R1 = 0.078 (wR2 = 0.185) on the basis of 1678 unique reflections. The (NH4)2Fe3+Cl5·H2O phase is orthorhombic, space group Pnma, unit cell parameters a = 13.725(2), b = 9.9365(16), c = 7.0370(11) Å and V = 959.7(3) Å3. The crystal structure of (NH4)2Fe3+Cl5·H2O was refined to R1 = 0.023 (wR2 = 0.066) on the basis of 2256 unique reflections. NH4MgCl3·6H2O is stable up to 90 °C and then transforms to the less hydrated phase isotypic to β-Rb(MnCl3)(H2O)2 (i.e., NH4MgCl3·2H2O), the latter phase being stable up to 150 °C. (NH4)2Fe3+Cl5·H2O is stable up to 120 °C and then transforms to an X-ray amorphous phase. Hydrogen bonds provide an important linkage between the main structural units and play the key role in determining structural stability and physical properties of the studied phases. The mineral phases NH4MgCl3·6H2O and (NH4)2Fe3+Cl5·H2O are isostructural with natural minerals novograblenovite and kremersite, respectively.

Catalytic Hydrolysis of Phosphate Monoester by Supramolecular Phosphatases Formed from a Monoalkylated Dizinc(II) Complex, Cyclic Diimide Units, and Copper(II) in Two-Phase Solvent System.

Design and synthesis of enzyme mimic with programmed molecular interaction among several building blocks including metal complexes and metal chelators is of intellectual and practical significance. The preparation of artificial enzymes that mimic the natural enzymes such as hydrolases, phosphatases, etc. remains a great challenge in the field of supramolecular chemistry. Herein we report on the design and synthesis of asymmetric (nonsymmetric) supermolecules by the 2:2:2 self-assembly of an amphiphilic zinc(II)-cyclen complex containing a 2,2'-bipyridyl linker and one long alkyl chain (Zn2L3), barbital analogues, and Cu2+ as model compounds of an enzyme alkaline phosphatase that catalyzes the hydrolysis of phosphate monoesters such as mono(4-nitrophenyl)phosphate at neutral pH in two-phase solvent system (H2O/CHCl3) in pH 7.4 and 37 °C. Hydrolytic activity of these complexes was found to be catalytic, and their catalytic turnover numbers are 3-4. The mechanistic studies based on the UV/vis and emission spectra of the H2O and CHCl3 phases of the reaction mixtures suggest that the hydrophilicity/hydrophobicity balance of the supramolecular catalysts is an important factor for catalytic activity.

Top-down synthesis of iron fluoride/reduced graphene nanocomposite for high performance lithium-ion battery

To fabricate reliable conducting matrix for highly insulated iron fluoride, we design a facile, green and low-cost solvothermal based synthesis method using graphene oxide powders and commercial FeF3·3H2O as precursors for the preparation of FeF3·0.33H2O/reduced graphene oxide (denoted as FeF3·0.33H2O/rGO) nanocomposite, as it is achieved by a combination of self-assembly, top-down phase transformation and solvothermal reduction processes. The 1D tunnel structure of FeF3·0.33H2O phase, nanoscale size and graphene conductive matrix together ensure ultrafast Li ion and electron transport. When applied as a cathode in lithium-ion batteries, the FeF3·0.33H2O/rGO electrode displays durable long-term cyclability (98% capacity retention over 100 cycles at 0.5C) and impressive rate capability (122 mAh g−1 at 10C), wherein surface-induced capacitive process plays an important role. Meanwhile, we also demonstrate the successful preparation of FeF2/reduced graphene oxide (denoted as FeF2/rGO) nanocomposite through adaption of reaction temperature, which has been seldom synthesized and here also exhibits high electroactivity.

Metal-Support Cooperative Effects in Au/VPO for the Aerobic Oxidation of Benzyl Alcohol to Benzyl Benzoate.

This paper studies the cooperative effect of Au nanoparticles deposited on vanadyl pyrophosphate oxide (VPO) in the liquid phase oxidation of benzyl alcohol. VPO was prepared using the classical method by thermally treating VOHPO4·0.5H2O precursor in reacting atmosphere at 420 °C for a period of 72 h. Au nanoparticles were deposited by incipient wetness method. The catalysts were characterized by means of XRD, TEM, XPS and Raman. The bulk VPO catalyst contains vanadyl pyrophosphate phase ((VO)2P2O7), and a small amount of VOPO4. The catalytic system exhibits a high activity in the base-free liquid phase oxidation of alcohols compared to Au on activated carbon, classic catalyst used for this type of reaction. Au/VPO showed a high peculiar selectivity to benzyl benzoate (76%), an important product used in the pharmaceutical and perfume industries. This behavior might be ascribed to the presence of strong acid sites of VPO, as determined by liquid phase titration. Stability tests performed on Au/VPO showed a deactivation of 10% after the first run, but a constant conversion along the following five cycles. This phenomenon can be attributed to the increase of mean Au particle size (from 19.1 to 23.4 nm) after recycling tests as well as the partial leaching of Au and V in the reaction media. Moreover, XRD evidenced a modification in the VPO structure with the partial formation of VOHPO4·0.5H2O phase.

The influence of the H5⋯O[dbnd]C4 intramolecular hydrogen-bond (IHB) on the antioxidative activity of flavonoid

Flavonoids widely found in natural foods are characterized by acting as antioxidants compounds. There are close relationship between the antiradical activities and structural properties of flavonoids. In this work, density functional theory (DFT) methods were applied to investigate the influence of the H5⋯OC4 intramolecular hydrogen-bond (IHB) on the antiradical activity of flavonoid based on three prevalently accepted radical scavenging mechanisms: hydrogen atom transfer (HAT), single electron transfer-proton transfer (SET-PT) and sequential proton-loss electron-transfer (SPLET). The thermodynamic properties: bond dissociation enthalpy (BDE), ionization potential (IP), proton dissociation enthalpy (PDE), proton affinity (PA) and electron transfer enthalpy (ETE) related with these mechanisms were calculated to elucidate the antiradical activity. The results showed that the 5−OH group is most influenced and its antiradical capacity was weakened by the H5⋯OC4 IHB. In the gas, benzene and chloroform phases, H5⋯OC4 IHB would reduce the antiradical activity of flavonoid via increasing the bond dissociation enthalpy. While, in the DMSO and H2O phases, the opposite result occurs by lowering the proton affinity.

Mechanism of enhanced oxidation ability of dilute nitric acid and dissolution of pure gold in seawater with nitric acid

It has been discovered that dilute nitric acid in reversed micelle systems can oxidize the Br- ion to Br2 and we have proposed that the nitryl (or nitronium) ion NO2+ should be the active species in the oxidation process. Nitration of phenol in reversed micelle systems with dilute nitric acid, CHCl3/CTAC/H2O (2.0 mol dm-3 HNO3 in the 1.0% (v/v) H2O phase), has been performed at 35 oC to obtain 2- and 4-nitrophenols, where CTAC represents cetyltrimethylammonium chloride. In aqueous 2.0 mol dm-3 HNO3 solution accompanied by 4.0 mol dm-3 LiCl (and a small amount of LiBr as the bromide resource), trans-1,4-dibromo-2-butene was successfully brominated to 1,2,3,4-tetrabromobutane. This result is good evidence that the Br- ion can be oxidized to Br2 in dilute nitric acid (2.0 mol dm-3) providing it contains concentrated salts. For chloride salts, the cation effects increased as Et4N+ << Na+ < Li+ < Ca2+ < Mg2+. Even the evolution of Cl2 has been demonstrated from < 2.0 mol dm-3 HNO3 solution containing concentrated LiCl, MgCl2, and CaCl2 as well as AlCl3. The dissolution of precious metals (Au, Pt, and Pd), especially, of gold has been demonstrated in 0.1 - 2 mol dm-3 HNO3 accompanied by alkali metal, alkaline earth metal, and aluminum chlorides. The complete dissolution time of pure gold plate (20±2 mg, 0.1 mm thickness) in 2.0 mol dm-3 HNO3 accompanied by 1.0 mol dm-3 AlCl3 has been shortened remarkably with temperature increase from 15 to 80 oC. The dissolution rate constants, log (k /s-1), of a piece of gold wire (19.7±0.5 mg) in 20 mL of 2.0 mol dm-3 HNO3 accompanied by the metal chlorides, in general, increase with increasing salt concentrations at 40 and 60 oC. The gold can be dissolved in the solution of <1.0 mol dm-3 HNO3 and <1.0 mol dm-3 HCl, i.e. a “dilute aqua regia. We have achieved a total dissolution of five pieces of the gold wire (totally 0.10 g) in 100 mL of the 1:1 mixture between seawater and 2.0 mol dm-3 HNO3 at ca. 100 oC.

The Twofold Role of 12-Hydroxyoctadecanoic Acid (12-HOA) in a Ternary Water-Surfactant-12-HOA System: Gelator and Co-Surfactant.

Gelled lyotropic liquid crystals can be formed by adding a gelator to a mixture of surfactant and solvent. If the gel network and the liquid-crystalline phase coexist without influencing each other, the self-assembly is called orthogonal. In this study, the influence of the organogelator 12-hydroxyoctadecanoic acid (12-HOA) on the lamellar and hexagonal liquid crystalline phases of the binary system H2O–C12E7 (heptaethylene glycol monododecyl ether) is investigated. More precisely, we added 12-HOA at mass fractions from 0.015 to 0.05 and studied the resulting phase diagram of the system H2O–C12E7 by visual observation of birefringence and by 2H NMR spectroscopy. In addition, the dynamic shear moduli of the samples were measured in order to examine their gel character. The results show that 12-HOA is partly acting as co-surfactant, manifested by the destabilization of the hexagonal phase and the stabilization of the lamellar phase. The higher the total surfactant concentration, the more 12-HOA is incorporated in the surfactant layer. Accordingly, its gelation capacity is substantially reduced in the surfactant solution compared to the system 12-HOA–n-decane, and large amounts of gelator are required for gels to form, especially in the lamellar phase.

Influence of H2O phase state on system efficiency in O2/H2O combustion power plant

In this work, oxy-fuel combustion with H2O as diluent in natural gas power plant is proposed, and the effect of phases of H2O on the overall system efficiency is investigated. Three different phase states of H2O, liquid water, steam and liquid-steam mixture are investigated, and the corresponding systems GST-L, GT-S and GT-M system are simulated and compared. To overcome the problem that the steam Rankin cycle cannot fully utilize the latent heat of water, the transcritical CO2 (T-CO2) cycle is introduced. The thermal analysis results show that the GT-M system with steam-water mixture as diluent performs the best, and the energy and exergy efficiency is 60.86% and 49.29%, respectively. The GST-L system takes the second place, and the GT-S system shows the lowest efficiency. The results reveal that steam-water mixture is the best phase of H2O recycled to control the combustion temperature, and the integration of gas turbine and T-CO2 cycle can fully utilize the thermal energy of flue gas to generate electricity. Therefore, the high-efficiency power generation with near-zero carbon emissions is achieved.

Multicomponent Vapor–Liquid Equilibrium Measurement and Modeling of Ethylene Glycol, Water, and Natural Gas Mixtures at 6 and 12.5 MPa

High pressure subsea natural gas dehydration (NGD) units using ethylene glycol (MEG) absorption have been proposed. To expand the experimental database and assist design qualification, new vapor–liquid equilibrium (VLE) experimental data have been measured for a 20-component glycol–water–natural gas mixture at T = (288–323) K, p = (6.0, 12.5) MPa, and wMEG,feed = (90, >99.8) %. MEG, H2O, CO2, N2, and alkane (methane to n- and i-pentane) phase distributions have been quantified. Experimental uncertainty ranges from ±2–42%, with the greatest uncertainty for the quantification of trace components. Experimental results are modeled using the Cubic-Plus-Association (CPA) equation of state. Overpredictions (∼9%) are observed for the water content of the vapor phase. CO2 is shown to have a large effect on yMEG, leading to modeling deviations in the order of 65%. A relatively accurate prediction of the natural gas partition coefficients was observed for major components C1–C3 and CO2, with modeling errors ranging from 5% for methane to 10% for CO2. More significant deviations were observed for trace components, with the largest deviation of 73% N2. The CPA model provides both satisfactory and conservative results suitable for use in NGD process designs. On the basis of this work, operation at subsea conditions would significantly improve dehydration capability.

Simultaneous determination of the novel anti-tumor candidate drug MDH-7 and 5-fluorouracil in rat plasma by LC-MS/MS: Application to pharmacokinetic interactions

MDH-7 (2,3,9-tri-O-acetyl-5,6-dideoxy-1,10-di-[N4′-pentoxycarbonyl-5′-fluoro cytosine]-4-ulose 1,4: 7,10-difuranose-4,8-pyranose) is a novel anti-tumor drug candidate. To study the pharmacokinetic interaction between MDH-7 and 5-fluorouracil (5-FU), a sensitive and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed to simultaneously determine the concentrations of MDH-7 and 5-fluorouracil (5-FU) in rat plasma. Plasma samples were prepared by simple liquid-liquid extraction with ethyl acetate. Chromatographic separation was performed on a Waters XBridge™ C18 column (5 μm, 2.1 mm × 150 mm) with the mobile phase of methanol and H2O (80:20, v/v). The ESI positive and negative ion switch was operated in the multiple reactions monitoring (MRM) mode. The calibration curves showed good linearity (r2 > 0.99) over the ranges of 50–8000 ng/mL for MDH-7 and 10–2000 ng/mL for 5-FU, respectively. The lower limit of quantitations (LLOQs) was 50 ng/mL (MDH-7) and 10 ng/mL (5-FU) with relative standard deviation (RSD) < 13.0%. The proposed method was successfully applied to simultaneous assessment of pharmacokinetic drug-drug interaction between MDH-7 and 5-FU in rats.

Binary-Phase Acetonitrile and Water Aerosols: Infrared Studies and Theoretical Simulation at Titan Atmosphere Conditions

Acetonitrile (CH3CN) and water (H2O) ice particles were generated within a collisional cooling cell coupled to the Australian Synchrotron light source. The evolution of the aerosols was tracked by infrared spectroscopy compiled over the 4000–50 cm–1 region. Gas pressure and temperature conditions were varied to replicate the lower altitudes of the Titan atmosphere allowing for comparison to far-infrared features detected by the Cassini–Huygens spacecraft. The experimental spectra show that CH3CN and H2O particles are microheterogeneous in composition and spherical in shape. CH3CN lattice bands display temperature-dependent shifts in frequency, implying that pure β-phase is present in the mixed particles. In addition, a red shift identified for the C≡N fundamental stretching mode indicates dipole–dipole and π-electron side-directed hydrogen bond coupling between segregated CH3CN and H2O phases exclusively at the grain interface. Discrete dipole approximation theory was implemented to evaluate various clust...

Cryosphere: a kingdom of anomalies and diversity

Abstract. The cryosphere of the Earth overlaps with the atmosphere, hydrosphere and lithosphere over vast areas with temperatures below 0 ∘C and pronounced H2O phase changes. In spite of its strong variability in space and time, the cryosphere plays the role of a global thermostat, keeping the thermal regime on the Earth within rather narrow limits, affording continuation of the conditions needed for the maintenance of life. Objects and processes related to cryosphere are very diverse, due to the following basic reasons: the anomalous thermodynamic and electromagnetic properties of H2O, the intermediate intensity of hydrogen bonds and the wide spread of cryogenic systems all over the Earth. However, these features attract insufficient attention from research communities. Cryology is usually understood as a descriptive discipline within physical geography, limited to glaciology and permafrost research. We emphasise its broad interdisciplinary landscape involving physical, chemical and biological phenomena related to the H2O phase transitions and various forms of ice. This paper aims to draw the attention of readers to the crucial importance of cryogenic anomalies, which make the Earth atmosphere and the entire Earth system very special, if not unique, objects in the universe.

Absorption and dispersion of low-frequency sound waves in the main cloud layers of Venus

We present predictions for the acoustic wavenumbers at low frequencies in the condensational cloud layers of Venus, occurring between 50 and 70 km, approximately. While the general thermodynamics of Earth clouds is well understood, that of Venusian clouds is still a matter of debate. Venus' clouds are formed primarily of H2O and H2SO4 vapors and aqueous sulfuric acid droplets, the fluxes of which are not fully constrained due to the few insitu observations. This study is based on and adapted from the terrestrial model of Baudoin et al. (J. Acoust. Soc. Am. 130, 1142 (2011)). Inside the clouds, the Navier-Stokes equations of continuum fluid mechanics are used for the gaseous (dry + vapor) and liquid phases of H2O and H2SO4, combined with the equations describing the evaporation/condensation processes; the gaseous phase is treated as an ideal gas. Outside the clouds, in the CO2—dominated atmosphere, the van der Waals equation of state is used. [The work was supported by a Grant from the Louisiana Space Consortium (LaSPACE).]

Sol-gel synthesis, structural refinement, and electrochemical properties of potassium manganese phosphate for supercapacitors

Using sol-gel thermolysis method, potassium manganese phosphate (a mixture of KMnPO4⋅H2O and KMnPO4 phases) was synthesized for supercapacitor applications. XRD analysis revealed phase composition and crystal structure of the prepared material. The dittmarite-type structure of KMnPO4⋅H2O as the primary phase was identified through full profile Rietveld refinement technique. The possible four normal modes of vibrations ν1(A1), ν2(E), ν3(F2), and ν4(F2) were analyzed through FTIR spectrum. Submicron-sized particles are identified using FE-SEM and TEM images. The layered structure of potassium manganese phosphate was corroborated through SAED pattern. Electrochemical performances of the mixed potassium manganese phosphate are investigated using cyclic voltammetry (CV) to identify the suitable aqueous electrolytes (1 M KOH, 1 M LiOH, and 1 M NaOH). It provides the maximum specific capacitance of 516 F g−1 at 2 mV s−1 in 1 M KOH aqueous electrolyte. The Trasatti plot revealed that the observed high specific capacitance mainly arises from the inner surface charge contribution. The electrode shows the better specific capacity of 329 F g−1 at a current density of 0.6 mA cm−2 in galvanostatic charge-discharge measurements. The electrochemical impedance spectral analysis (EIS) further corroborates that the charge-transfer resistance (Rct) is low in 1 M KOH (2.25 Ω) electrolyte than in 1 M LiOH (9.2 Ω) and 1 M NaOH (50.7 Ω) electrolytes.

Applying Semi-Empirical Quantum Harmonic Calculations for Studying the Atomic Kinetic Energies in Hydrogen Bonded Systems

The use of the semi empirical (SE) quantum harmonic approach for calculating the proton’s mean kinetic energy, Ke(H), of systems containing hydrogen bonds (HB), is reviewed. The value of Ke(H) provides very interesting information on the proton dynamics, anharmonicity, and quantum effects. This method uses the IR/Raman and inelastic neutron scattering frequencies of the system as input data and assumes the harmonic approximation. The systems studied encompass a wide range of HBs strengths, from weak occurring in e.g. pure H2O phases and Silanol groups, via moderate, as in ferro-electric KDP-type crystals, to strong ones as in highly compressed ice VII and the superprotonic Rb3H(SO4)2 conductor. The comparison of SE results with electron (ECS) and neutron (NCS) Compton scattering measurements revealed many cases of very good agreements. In recent years, however, unusual Ke(H) values, using NCS, were reported in confined water within ≤ 20 Å size cavities such as in carbon nanotubes (CNTs) and in Beryl crystal. The Ke(H) values were found to depart strongly from those of the non-confined water. In an attempt to understand those anomalies, SE study was carried out, focusing on nano-confined samples meeting the ≤ 20Å size criteria, including carbon nanotubes, Beryl and Bikitaite. These calculations failed to reproduce the NCS anomalies. Possible sources for the discrepancies were discussed and further research to reconcile this open question was proposed. Keywords: Harmonic approximation, hydrogen bonds, kinetic energy, libration, nano-confinement, neutron scattering, proton, vibrational density of states.

Theoretical studies on the antioxidant activity of pinobanksin and its ester derivatives: Effects of the chain length and solvent

The effects of the ester group and solvent on the structure and antioxidant activity of pinobanksin were carried out using DFT calculation. First, the properties of the intramolecular hydrogen-bonds in the investigated compounds were studied. Second, the antioxidant capacities of the investigated compounds were analyzed by HAT, SET-PT and SPLET mechanisms from thermodynamic point. The conclusions are: (1) HAT mechanism is most favorable in the gas and CCl4 phases, while SPLET mechanism is more favored in the CH3CN and H2O phases. In the CHCl3 phase, the thermodynamically preferred mechanism is HAT for the 3−OH and 5−OH groups. While, HAT and SPLET mechanisms may run simultaneously for the 7−OH group. (2) Replacing the 3−OH group by ester group with different alkyl chains does not change much of the antioxidant activity of pinobanksin. (3) Besides, the 7−OH group contributes mainly to the antioxidant activities of the investigated compounds.

Air-stable hydrogen generation materials and enhanced hydrolysis performance of MgH 2 -LiNH 2 composites

Abstract Hydrolysis of materials in water can be a promising solution of onsite hydrogen generation for realization of hydrogen economy. In this work, it was the first time that the MgH2-LiNH2 composites were explored as air-stable hydrolysis system for hydrogen generation. The MgH2-LiNH2 composites with different composition ratios were synthesized by ball milling with various durations and the hydrogen generation performances of the composite samples were investigated and compared. X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy techniques were adopted to elucidate the performance improvement mechanisms. The hydrolysis properties of MgH2 were found to be significantly enhanced by the introduction of LiNH2. The 4MgH2-LiNH2 composite ball milled for 5 h can generate 887.2 mL g−1 hydrogen in 1 min and 1016 mL g−1 in 50 min, one of the best results so far for Mg based hydrolysis materials. The LiOH·H2O and NH4OH phases of hydrolysis products from LiNH2 may prevent formation of Mg(OH)2 passivation layer on the surface and supply enough channels for hydrolysis of MgH2. The MgH2-LiNH2 composites appeared to be very stable in air and no obvious negative effect on kinetics and hydrogen generation yield was observed. These good performances demonstrate that the studied MgH2-LiNH2 composites can be a promising and practicable hydrogen generation system.

Polytherm of the CO(NH2)2–KNO3–H2O phase diagram

The crystallization polytherm of the ternary CO(NH2)2–KNO3–H2O system is plotted for the first time via visual polythermal analysis and calculating ternary eutonics characteristics from data on the boundary elements of two-component systems. The ternary eutonics modeling error does not exceed 3.5%. In addition to the crystallization fields of individual components, the field of the redox reaction that occurs in the system between potassium nitrate and carbamide is shown in the CO(NH2)2–KNO3–H2O diagram by a dashed outline.

Remnant Massifs of Layered Deposits at High Northern Latitudes of Mars

Ice deposits of the permanent northern polar cap of Mars exhibit a clearly expressed layered structure connected with consecutive accumulation of a solid phase of H2O (ice) with different impurity fractions of dust. The observed structure of the northern polar cap deposits is direct evidence of the uneven accumulation of ice associated with climate variations on Mars over a long period of time. Outside the boundaries of the present northern polar cap, there are isolated remnant massifs of bright deposits with a clearly distinguishable layered structure. In this paper, we analyze the morphology, spatial distribution, and material composition of remnant massifs within the latitude belt of 60°–85°. The similarity in the structure and material composition found in the remnant massifs and the layered deposits of the northern polar cap of Mars apparently suggests that these formations were genetically connected in the past climatic epochs.