The crystal structure of aluminium, iron (III), and gallium acid phosphites
- PDF / 194,312 Bytes
- 4 Pages / 612 x 792 pts (letter) Page_size
- 34 Downloads / 178 Views
CTURE OF INORGANIC COMPOUNDS Dedicated to the memory of G. B. Bokiі on the occasion of his 100th birthday
The Crystal Structure of Aluminium, Iron (III), and Gallium Acid Phosphites B. S. Zakharova† and A. B. Ilyukhin Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninskiі pr. 31, Moscow, 119991 Russia email: [email protected] Received January 27, 2009
Abstract—The structures of three acid phosphites of trivalent metals [Al(HPO3H)3(H2O)] · H2O (I), K[Fe(HPO3H4)] (II), and Rb3[Ga(HPO3H)6] (III) have been determined. Structure I is layered, complex anions [Fe(HPO3H)4]– form polymer chains in structure II, and structure III is insular. DOI: 10.1134/S1063774510010049
Inorganic phosphites are promising compounds for obtaining materials with desired properties. The presence of a hydrogen atom in a tetrahedral environ ment of trivalent phosphorus does not allow metal to occupy one of anion vertices and makes it possible to obtain chain or layered structures. It is known that such materials can be modified to change their prop erties. In this paper we report the results from studying the structure of three phosphites of trivalent metals: [Al(HPO3H)3(H2O)] · H2O (I), K[Fe(HPO3H)4] (II), and Rb3[Ga(HPO3H)6] (III).
inversion center in structure I was verified using the PLATON program [3].The small f" values of alumin ium and phosphorus did not allow us to determine the absolute crystal configuration. The structural data were deposited in the Inorganic Crystal Structure Database: CSD 420287–420289 for I–III, respec tively.
RESULTS AND DISCUSSION An aluminium atom in structure I has an octahe dral environment (typical of such compounds) formed by five oxygen atoms from five different phosphite
EXPERIMENTAL Crystals suitable for Xray diffraction analysis were obtained by dissolving oxides of the corresponding metals in melts of phosphorous acid at 90–100°С with the addition of potassium and rubidium hydroxides for compounds II and (I), respectively. Crystals I–III were studied by Xray diffraction. The main crystallographic parameters and results of structure refinement are presented in Table 1. The structures were identified by combining the direct method with consequent Fourier synthesis. All posi tions of hydrogen atoms in structure I were found from the difference Fourier maps. In structures I and II, only hydrogen atoms close to phosphorus were local ized. Structure I was refined by the anisotropic least squares method with due regard to fixed hydrogen atoms; structures II and III were refined by the iso tropic–anisotropic (H) method. The absence of an
a
b 0
c
†Deceased.
Fig. 1. Layer structure in compound I.
15
16
ZAKHAROVA, ILYUKHIN
Table 1. Crystallographic characteristics and experimental and refinement data for structures I–III Chemical formula
Al(HPO3H3)(H2O) ⋅ H2O
K[Fe(HPO3H)4]
Rb3[Ga(HPO3H)6]
System, sp.gr, Z
orthorhombic, Pna21, 4
monoclinic, P21/c, 2
trigonal, R 3 , 3
a, Å
8.1217(12)
5.1888(9)
14.8941(9)
b, Å
18.725(2)
7.1759(8)
c, Å
Data Loading...
