Triethylenediamine. II. Phase I at 354 K

Nimmo, J. K.; Lucas, B. W.

doi:10.1107/s0567740876003488

Cited by 39 publications

(47 citation statements)

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“…3 and 4 and described in Subsection 3.3, the ferroelectric phase in the bulk potassium nitrate is formed only during cooling, which is in complete agreement with the data available in the literature [20,21]. The temperature range of its existence is approxi mately equal to 24 K. This is consistent with the exist ε 3 bχ 4 -18b 2 P s χ 5 .…”

Section: Discussion Of the Resultssupporting

confidence: 87%

“…The samples were heated from room temperature to 463 K and then were cooled. It is known that, after heating to this tem perature, the ferroelectric phase is formed in bulk potassium nitrite [20,21]. It can be seen from Fig.…”

Section: Measurements Of the Linear Dielectric Permittivitymentioning

confidence: 87%

“…The spontaneous polarization is approximately equal to 8-10 μC/cm 2 at a temperature of 393 K [19]. It was found that the temperature range of the existence of the ferroelectric state in KNO 3 depends on the thermal prehistory and cooling rate [20,21] and, when the sample is preliminarily heated to 473 K, for the first heating-cooling cycle, it is approximately equal to 24 K.…”

Section: Sample Preparation and Experimental Techniquementioning

confidence: 96%

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Dielectric and calorimetric investigations of KNO3 in pores of nanoporous silica matrices MCM-41

et al. 2012

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The temperature dependences of the linear dielectric permittivity, the third harmonic amplitude, and the heat capacity of nanoporous silica matrices MCM 41 with cellular channels (3.7 and 2.6 nm in diam eter) filled with KNO 3 have been investigated in comparison with those obtained for bulk potassium nitrate. Measurements have been performed during heating and cooling in the range from room temperature to 463 K. Anomalies corresponding to structural phase transitions have been observed. A significant broadening of the temperature region of the existence of the ferroelectric phase III of potassium nitrate upon cooling has been revealed. This broadening increases with a decrease in the size of pores. It has been shown that, in the nanocomposites with potassium nitrate, the ferroelectric phase can also be formed during heating. The effi ciency of observation of the third harmonic generation for studying nanocomposites with the ferroelectric phase has been demonstrated.

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Section: Discussion Of the Resultssupporting

confidence: 87%

Section: Measurements Of the Linear Dielectric Permittivitymentioning

confidence: 87%

Section: Sample Preparation and Experimental Techniquementioning

confidence: 96%

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Dielectric and calorimetric investigations of KNO3 in pores of nanoporous silica matrices MCM-41

et al. 2012

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“…KNO 3 crystallizes in orthorhombical crystal system, space group Pnma [20]. Cr(NO 3 ) 3 ⋅ 9H 2 O crystallizes in monoclinic crystal system, space group Р2/са [21].…”

Section: Methodsmentioning

confidence: 99%

Study of the behavior of chromium(III) in potassium nitrate solutions at 25°C

Polishchuk¹,

Fakeev²,

Krasnova³

et al. 2012

Russ. J. Inorg. Chem.

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458Potassium nitrate of high purity grade is used in several new fields of industry (optics, fiber optics, etc.) that impose high requirements to the content of impu rities that give color to glass (including chromium) [1].No solubility data for the KNO 3 -Cr(NO 3 ) 3 -H 2 O system at 25°С have been found in literature. Only the solubilities of potassium and chromium nitrates in water at 25°С have been determined; their values are 27.39 [2], 27.52 [3], 27.94 [4], and 44.80 wt % [5, 6], respectively. Cr(NO 3 ) 3 ⋅ 9H 2 O of pure grade and pure for analysis grade are commercially available (GOST 4471) [7].In aqueous solutions, chromium(III) in microcon centrations (≤1 × 10 -5 mol/L) exists in the form of a hydrated cation [Сr(H 2 O) 6 ] 3+ at pH 1.0-3.5; the for mation of a mononuclear hydroxo complex Cr(OH) 2+ was found at pH 3.5-4.0. The accumulation of Cr(OH) 2 + and complexes begins at pH > 5 and pH > 7, respectively [8].In this work the behavior of chromium(III) was studied in a wide range of concentrations in potassium nitrate solutions at 25°С. EXPERIMENTALTo gain data on the chromium(III) behavior in potassium nitrate solutions, the macro and micro concentration regions were studied.In the chromium(III)microconcentration range, the study was carried out by the solubility method. KNO 3 (high purity grade) (technical specifications 6 09 354) and chromium(III) nitrate (pure for analy sis grade; State Standard 4471) preliminarily recrystal lized from aqueous solutions and dried were used as initial materials. According to chemical analysis and IR spectra, the compounds corresponded to potas Cr(OH) 0 3 sium nitrate [9, 10] and chromium(III) nitrate non ahydrate [11].Potassium contents in samples of liquid phases and solid residues were determined by a gravimetric method [12], and chromium(III) contents, by a com plexonometry method [13]. The potassium and chro mium(III) contents when they were present together were found by analyzing two solution aliquots. To determine potassium, 0.6% aqueous solution of sodium tetraphenylborate was added to the first ali quot; the precipitate of potassium tetraphenylborate was transferred to a glass filter (POR 16), dried at 105°С to a constant weight, and weighed. To deter mine chromium(III), a precisely measured amount of 0.05 M Trilon B solution was added to the second ali quot and the mixture was boiled for 20 min. The solu tion was cooled, and the excess of 0.05 M Trilon B solution was titrated with 0.05 M zinc nitrate solution at pH 10.5-11.0 (ammonia buffered solution) in the presence of sulfarsazene (change in color from green to wine red). The metrological characteristics of the procedures (permissible discrepancies between two parallel definitions of 0.5 relative % and the relative value of a total analysis inaccuracy of 1.5%) were determined by variance analysis.The IR spectra of solid phases were taken on a Per kin Elmer 983 G spectrophotometer in the range of 200-4000 cm -1 . Samples were prepared pressing tab lets with potassium bromide.Chromium microamounts were ...

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“…(i) Triethylenediamine (N(CH2CH2)3N) by x-ray powder diffraction (Nimmo and Lucas 1976). The space group is Fm3m with 2 = 4.…”

Section: Introductionmentioning

confidence: 99%

High-power excimer lasers and new sources of coherent radiation in the vacuum ultraviolet

Попов¹

1985

Sov. Phys. Usp.

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Single crystal x-ray diffraction data were collected and interpreted for the plastic phase of bicyclo (2.2.2) octane [CH(CH2CH&CH] at T = 265 K. In order to determine the structure of this phase, several refinement procedures are tried: Frenlcel models (jump model and free rotation around threefold axes), decomposition of the orientational probability of molecules on symmetry-adapted functions. The best fit (Rw = 4.7%) is obtained with the last model. The maximum of the orientational probability occurs when the threefold molecular and crystal axes are coincident. Around each (111) direction the molecular rotation is a 'quasi' free rotation.

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Triethylenediamine. II. Phase I at 354 K

Cited by 39 publications

References 1 publication

Dielectric and calorimetric investigations of KNO3 in pores of nanoporous silica matrices MCM-41

Dielectric and calorimetric investigations of KNO3 in pores of nanoporous silica matrices MCM-41

Study of the behavior of chromium(III) in potassium nitrate solutions at 25°C

High-power excimer lasers and new sources of coherent radiation in the vacuum ultraviolet

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