Präparative Festkörperchemie mit CO<sub>2</sub>‐Hochleistungslasern

Möhr, S.; Müller‐Buschbaum, Hk.

doi:10.1002/ange.19951070605

Cited by 11 publications

(5 citation statements)

References 92 publications

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“…[8] The application of this procedure to the synthesis of nitrides seems to be technically difficult, because the evolution of N 2 by dissociation of the nitrides is not reversible below 900 8C for kinetic reasons. Recently Weller et al obtained the nitrides Ca 2 AuN and Li 3Àx Cu x N under a pressure of 200 bar using autoclaves.…”

Section: Introductionmentioning

confidence: 99%

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High-Temperature High-Pressure Synthesis of the Highly Condensed Nitridophosphates NaP4N7, KP4N7, RbP4N7, and CsP4N7 and Their Crystal-Structure Determinations by X-ray Powder Diffraction

Landskron¹,

Irran²,

Schnick³

1999

Chem. Eur. J.

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The nitridophosphates NaP 4 N 7 , KP 4 N 7 , RbP 4 N 7 , and CsP 4 N 7 were synthesized by the reaction of the respective alkali metal azides with P 3 N 5 in a belt apparatus at 40 kbar and 1800 ± 2000 8C. The products were obtained as colorless crystalline powders. As compared to all other nitridophosphates obtained so far the temperature of synthesis could be raised by 1000 8C. Thus a convenient crystallization of the novel highly condensed nitridophosphates was achieved. The crystal structures were solved by direct methods on the basis of X-ray powder diffraction data and refined by the Rietveld method (NaP 4 N 7 : is isotypic with the oxides M(M') 4 O 7 (M Ca, Sr; M' Al, Ga). The crystal structure of KP 4 N 7 , RbP 4 N 7 , and CsP 4 N 7 is the aristotype of the mineral barylite, BaBe 2 Si 2 O 7 .

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Section: Introductionmentioning

confidence: 99%

“…The alkali ions (K , Rb , and Cs ) are positioned in Table 4. Interatomic distances [pm] and angles [8] in NaP 4 N 7 .…”

Section: Introductionmentioning

confidence: 99%

High-Temperature High-Pressure Synthesis of the Highly Condensed Nitridophosphates NaP4N7, KP4N7, RbP4N7, and CsP4N7 and Their Crystal-Structure Determinations by X-ray Powder Diffraction

Landskron¹,

Irran²,

Schnick³

1999

Chem. Eur. J.

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“…Dark‐brown microcrystalline substances were obtained, which were molded into pellets. These were melted in argon at 1800 °C with the CO 2 ‐LASER method63 and annealed for 10 min. Within the next 20 min the power of the LASER was reduced and the temperature was lowered to 600 °C before the power was completely turned off.…”

Section: Alkaline Earth and Rare Earth Oxocobaltates A Mln2coo5mentioning

confidence: 99%

On the Crystal Chemistry of Alkaline Earth‐ and Rare Earth‐Oxocobaltates

Müller‐Buschbaum

2013

Zeitschrift anorg allge chemie

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A review on the crystal chemistry of oxocobaltates of alkaline earth and rare earth metals is presented according to the formula of the compounds, based on increasing metal and oxygen content. The well‐known structures of perowskites and K2NiF4‐type compounds and their higher homologues have been ignored and cross‐referred to older publications. Cobalt shows mainly the oxidation states Co2+ and Co3+. In many cases it exhibits integer valences like Co2.28+, Co2.5+, Co2.54+, Co2.8+, Co3.5, and Co3.6+, referred in the ICSD database. The dominant coordination polyhedra are CoO4‐tetrahedra and CoO6‐oktahedra. In two cases a trigonal prismatic CoO6‐coordination is observed. Composition, crystal structure, and oxidation state of cobalt often depend on the preparation conditions. In contrast to the alkaline oxides, the alkaline earth and rare earth oxides used for preparations are less reactive. Therefore the necessary reaction temperatures are much higher. In these cases single crystals for x‐ray investigation were prepared by plasma‐burner and CO2‐LASER techniques.

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“…Die Darstellung erfolgte bei hohen Temperaturen. Hierzu werden Presslinge aus BaCO 3 :NiCO 3 : Ln 2 O 3 (1:1:1) 12 h bei 1100 °C vorgesintert und anschließend mit der CO 2 ‐LASER‐Technik75 kurzzeitig auf 2000 °C erhitzt (pyrometrisch gemessene Oberflächentemperatur). Die in der Vorreaktion bereits ausgebildete Zusammensetzung Ba Ln 2 NiO 5 führt unter dem Einfluss der hohen Temperaturen zu einkristallinem Material.…”

Section: F Erdakalimetall/lanthanoid‐oxoniccolateunclassified

Zur Kristallchemie von Oxoniccolaten der Alkali‐, Erdalkali‐ und Seltenerdmetalle

Müller‐Buschbaum

2011

Zeitschrift anorg allge chemie

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This review describes features of the crystal chemistry of oxoniccolates containing large cations like alkali‐, alkaline earth and rare earth metals. Starting with alkali‐oxoniccolates it is shown that Ni+ exhibits the unusual coordination number CN = 2 (dumbbells) in K2/ Rb2/ Na2NiO2 and K3NiO2. K2NiO2 is the only known oxoniccolat showing O–Ni–O‐dumbbells with nickel in the oxidation state Ni2+. The trigonal planar coordination (found within silver‐oxocompounds) is restricted to Ba3NiO4 and K9Ni2O7. Square planar polygons (NiO4) are found in Nd4Ni3O8; Na2NiO2; Ki2NiO2; BaNiO2 and SrNiO2 for example. A special quality in the crystal chemistry of connected square planar NiO4‐polygons is the formation of Ni6O12‐rings in Ba2NaNi3O6. There are two compounds showing Ni3+O4‐tetrahedra: K9Ni2O7 and Na5NiO4. All the other oxoniccolates exhibit octahedral or trigonal prismatic coordination of nickel by oxygen. Always of interest are the so called one dimensional oxides, showing chains of two times face‐shared octahedra and/or trigonal prisms, found in Sr3Yb0.89NiO6, Sr3PbNiO6; Sr12Ni7.5O27; Sr4Ni3O9; BaNi0.83O2.5 and NaSr12Ni7O23. Large chains of the type –[(octahedron)2–(prism)–(octahedron)2–prism–(octahedron)3–(prism)–(octahedron)2–(prism)–(octahedron)2]– filled by Ni3+ and Ni4+ are found in Sr9Ni6.64O21. Many of the oxidation states of nickel are published with non integral valence states like Ni2.667+, Ni2.5+, Ni2.292+, Ni3.614. Using calculations of the Coulomb‐terms of lattice energy most of the mixed valences could be split up in integral numbers protecting the electro neutrality between metal ions and oxygen.

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Präparative Festkörperchemie mit CO₂‐Hochleistungslasern

Cited by 11 publications

References 92 publications

High-Temperature High-Pressure Synthesis of the Highly Condensed Nitridophosphates NaP4N7, KP4N7, RbP4N7, and CsP4N7 and Their Crystal-Structure Determinations by X-ray Powder Diffraction

High-Temperature High-Pressure Synthesis of the Highly Condensed Nitridophosphates NaP4N7, KP4N7, RbP4N7, and CsP4N7 and Their Crystal-Structure Determinations by X-ray Powder Diffraction

On the Crystal Chemistry of Alkaline Earth‐ and Rare Earth‐Oxocobaltates

Zur Kristallchemie von Oxoniccolaten der Alkali‐, Erdalkali‐ und Seltenerdmetalle

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Präparative Festkörperchemie mit CO2‐Hochleistungslasern

Cited by 11 publications

References 92 publications

High-Temperature High-Pressure Synthesis of the Highly Condensed Nitridophosphates NaP4N7, KP4N7, RbP4N7, and CsP4N7 and Their Crystal-Structure Determinations by X-ray Powder Diffraction

High-Temperature High-Pressure Synthesis of the Highly Condensed Nitridophosphates NaP4N7, KP4N7, RbP4N7, and CsP4N7 and Their Crystal-Structure Determinations by X-ray Powder Diffraction

On the Crystal Chemistry of Alkaline Earth‐ and Rare Earth‐Oxocobaltates

Zur Kristallchemie von Oxoniccolaten der Alkali‐, Erdalkali‐ und Seltenerdmetalle

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Präparative Festkörperchemie mit CO₂‐Hochleistungslasern