ISSN:
0044-2313
Keywords:
Strontium
;
barium pnictide oxides
;
preparation
;
crystal structures
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Description / Table of Contents:
Preparation and Crystal Structure of the Alkaline Earth Pnictide Oxides Sr4P2O, Sr4As2O, Ba4P2O, and Ba4As2OSr4P2O (light-brown), Sr4As2O (red-brown), Ba4As2O (grey-black), and Ba4P2O (grey-black) were prepared by the reaction of the metals, red phosphorus (arsenic), and metal oxide in molar ratios 3 : 2 : 1 in corundum crucibles sealed in quartz ampoules under argon (3 d 630°C, 2 d 1000°C, 2 d 1100°C). The compounds are microcrystalline, easily hydrolysable powders. Black single crystals of Ba4As2O and Ba4P2O were obtained by annealing specimens in molybdenum ampoules under argon (3 d 1200 and 1300°C resp.).Sr4P2O, Sr4As2O, and Ba4As2O crystallize in the K2NiF4-type structure; Ba4P2O is rhombically distorted and possesses the La2CuO4-type structure (Crystallographic data: see “Inhaltsübersicht”). The influence of the size of the pnictide ion (Pn = P to Bi) on crystal chemical properties of the compounds M4Pn2O with the same cation is discussed.
Notes:
Sr4P2O (hellbraun), Sr4As2O (rotbraun), Ba4As2O (grauschwarz) und Ba4P2O (grauschwarz) wurden als mikrokristalline, hydrolyseempfindliche Pulver aus Metall, rotem Phosphor bzw. Arsen und Metalloxid im Molverhältnis 3 : 2 : 1 in Korundinnentiegeln in Quarzampullen unter Argon dargestellt (3 d 630°C, 2 d 1000°C, 2 d 1100°C). Schwarze Kristalle des Ba4As2O und Ba4P2O erhielt man durch dreitägiges Tempern der Präparate in Molybdänampullen unter Argon bei 1200 bzw. 1300°C.Sr4P2O, Sr4As2O und Ba4As2O kristallisieren im K2NiF4-Typ (I 4/m m m, Z = 2): Sr4P2O: a = 479,4(1) pm, c = 1598,5(4) pm, d254 = 3,90; Sr4As2O: a = 483,1(1) pm, c = 1636,4(4) pm, d254 = 4,46; Ba4As2O: a = 512,46(4) pm, c = 1733,6(1) pm, d254 = 5,24.Ba4P2O ist rhombisch verzerrt (La2CuO4-Typ; Abma, Z = 4): a = 733,5(1) pm, b = 716,4(1) pm, c = 1673,2(3) pm, d254 = 4,71.Der Einfluß der Größe des Pnictidions (Pn = P bis Bi) auf kristallchemische Eigenschaften der Verbindungen M4Pn2O mit gleichem Kation wird diskutiert.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/zaac.19915970110
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