“…The main d values for β-Na 2 B 5 O 8 (OH)·2H 2 O are (10.876, 10.422, 6.022, 5.619, 5.436, 5.316, 5.195, 3.007, 2.904, 2.594, 2.821, 2.656, 2.5364, 2.455, and 2.257) Å. It can be seen that the latter shape and data of XRD patterns are different from those of the former, which confirms that β-Na 2 B 5 O 8 (OH)·2H 2 O is a new compound 1 Powder XRD patterns of synthesized samples (a) α-Na 2 B 5 O 8 (OH)·2H 2 O and (b) β-Na 2 B 5 O 8 (OH)·2H 2 O. 2 Simultaneous TG−DTA curves of an α-Na 2 B 5 O 8 (OH)·2H 2 O sample. …”
Section: Resultsmentioning
confidence: 78%
“…The band at 457 cm -1 might be the bending mode of B(4)−O. These absorption bands are different from those of β-Na 2 B 5 O 8 (OH)·2H 2 O …”
Section: Resultsmentioning
confidence: 91%
“…The thermal behavior of a β-Na 2 B 5 O 8 (OH)·2H 2 O sample has been given in a previous paper . The TG curve shows that β-Na 2 B 5 O 8 (OH)·2H 2 O has a three-step weight loss between (40 and 600) °C, and the total weight loss is 15.58 % (calcd, 16.01 %).…”
Section: Resultsmentioning
confidence: 96%
“…Synthesis and Characterization of Samples. A β-Na 2 B 5 O 8 (OH)·2H 2 O single-crystal sample was taken from our previous work . All reagents used in the synthesis of α-Na 2 B 5 O 8 (OH)·2H 2 O were of analytical grade.…”
Section: Methodsmentioning
confidence: 99%
“…Several phases, such as Na 2 B 5 O 8 (OH)·2H 2 O (nasinite), had been obtained in the Na 2 O−B 2 O 3 −H 2 O system under hydrothermal conditions . Recently, we obtained a new form of nasinite, and its synthesis and crystal structure have been reported . In this paper, we report the determination of the standard molar enthalpies of formation of the two polymorphs using a heat conduction microcalorimeter.…”
Two pure hydrated sodium borates, α-Na2B5O8(OH)·2H2O and β-Na2B5O8(OH)·2H2O, have been synthesized
under mild hydrothermal conditions and characterized by X-ray diffraction, infrared spectral, and thermogravimetric
analysis and chemical analysis. The molar enthalpies of solution of α-Na2B5O8(OH)·2H2O and β-Na2B5O8(OH)·2H2O in 1 mol·dm-3 HCl(aq) were measured by solution calorimetry to be (20.36 ± 0.33) kJ·mol-1 and (14.27
± 0.20) kJ·mol-1, respectively. With the incorporation of other thermodynamic data, the standard molar enthalpies
of formation were found to be −(4725.1 ± 4.0) kJ·mol-1 for α-Na2B5O8(OH)·2H2O and −(4719.0 ± 4.0) kJ·mol-1
for β-Na2B5O8(OH)·2H2O. The result shows that α-Na2B5O8(OH)·2H2O is more stable than β-Na2B5O8(OH)·2H2O, which is consistent with their thermal behavior.
“…The main d values for β-Na 2 B 5 O 8 (OH)·2H 2 O are (10.876, 10.422, 6.022, 5.619, 5.436, 5.316, 5.195, 3.007, 2.904, 2.594, 2.821, 2.656, 2.5364, 2.455, and 2.257) Å. It can be seen that the latter shape and data of XRD patterns are different from those of the former, which confirms that β-Na 2 B 5 O 8 (OH)·2H 2 O is a new compound 1 Powder XRD patterns of synthesized samples (a) α-Na 2 B 5 O 8 (OH)·2H 2 O and (b) β-Na 2 B 5 O 8 (OH)·2H 2 O. 2 Simultaneous TG−DTA curves of an α-Na 2 B 5 O 8 (OH)·2H 2 O sample. …”
Section: Resultsmentioning
confidence: 78%
“…The band at 457 cm -1 might be the bending mode of B(4)−O. These absorption bands are different from those of β-Na 2 B 5 O 8 (OH)·2H 2 O …”
Section: Resultsmentioning
confidence: 91%
“…The thermal behavior of a β-Na 2 B 5 O 8 (OH)·2H 2 O sample has been given in a previous paper . The TG curve shows that β-Na 2 B 5 O 8 (OH)·2H 2 O has a three-step weight loss between (40 and 600) °C, and the total weight loss is 15.58 % (calcd, 16.01 %).…”
Section: Resultsmentioning
confidence: 96%
“…Synthesis and Characterization of Samples. A β-Na 2 B 5 O 8 (OH)·2H 2 O single-crystal sample was taken from our previous work . All reagents used in the synthesis of α-Na 2 B 5 O 8 (OH)·2H 2 O were of analytical grade.…”
Section: Methodsmentioning
confidence: 99%
“…Several phases, such as Na 2 B 5 O 8 (OH)·2H 2 O (nasinite), had been obtained in the Na 2 O−B 2 O 3 −H 2 O system under hydrothermal conditions . Recently, we obtained a new form of nasinite, and its synthesis and crystal structure have been reported . In this paper, we report the determination of the standard molar enthalpies of formation of the two polymorphs using a heat conduction microcalorimeter.…”
Two pure hydrated sodium borates, α-Na2B5O8(OH)·2H2O and β-Na2B5O8(OH)·2H2O, have been synthesized
under mild hydrothermal conditions and characterized by X-ray diffraction, infrared spectral, and thermogravimetric
analysis and chemical analysis. The molar enthalpies of solution of α-Na2B5O8(OH)·2H2O and β-Na2B5O8(OH)·2H2O in 1 mol·dm-3 HCl(aq) were measured by solution calorimetry to be (20.36 ± 0.33) kJ·mol-1 and (14.27
± 0.20) kJ·mol-1, respectively. With the incorporation of other thermodynamic data, the standard molar enthalpies
of formation were found to be −(4725.1 ± 4.0) kJ·mol-1 for α-Na2B5O8(OH)·2H2O and −(4719.0 ± 4.0) kJ·mol-1
for β-Na2B5O8(OH)·2H2O. The result shows that α-Na2B5O8(OH)·2H2O is more stable than β-Na2B5O8(OH)·2H2O, which is consistent with their thermal behavior.
Sodium I 0500 Synthesis, Crystal Structure and Thermal Behavior of Na 4 [B 10 O 16 (OH) 2 ]·4H 2 O. -The title compound is prepared by reaction of Na2B4O7 and H3BO3 under mild hydrothermal conditions (H2O, 170°C, autoclave, 7 d). Na4[B10O16(OH)2]·4H2O crystallizes in the monoclinic space group Pc with Z = 2 (single crystal XRD). The structure consists of layers formed by the decaborate anions, which are interconnected by H-bonds to a three-dimensional framework with large tunnels. The Na + ions and water molecules form Na-O polyhedra within these tunnels. Dehydration of the compound occurs in three steps leading to an amorphous phase which undergoes crystallization. -(LIU*, Z.-H.; LI, L.-Q.; WANG, M.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
