The standardization of inorganic crystal-structure data

Parthé, E.; Gelato, Louise

doi:10.1107/s0108767384000416

Cited by 255 publications

(131 citation statements)

References 17 publications

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“…Unfortunately, definition (ii) is not an explicit and constructive definition since the exact meaning of 'similar geometric interrelationships' is not specified (Parthé & Gelato, 1984, 1985Burzlaff & Malinovsky, 1997;Bergerhoff et al, 1999), and thus novel methods that combine different criteria needed to be introduced. According to Lima-de-Faria et al (1990), we use an a priori definition of geometric criteria for distinguishing structure families.…”

Section: Introductionmentioning

confidence: 99%

“…Since the existing theoretical approaches to the definition of structure types (Parthé & Gelato, 1984, 1985Burzlaff & Malinovsky, 1997;Bergerhoff et al, 1999) already pointed at the difficulties one encounters when trying to determine structure types automatically, methods needed to be developed in order to be able to assign crystal structures contained in the ICSD to their corresponding structure types. This problem is also discussed in the first volume of structure types by Villars & Cenzual (2004).…”

Section: Introductionmentioning

confidence: 99%

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The introduction of structure types into the Inorganic Crystal Structure Database ICSD

Allmann¹,

Hinek²

2007

Acta Crystallogr A Found Crystallogr

200

134

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Both the approach used and the progress made in the assignment of structure types to the crystal structures contained in the ICSD database are reported. Extending earlier work, an hierarchical set of criteria for the separation of isopointal structures into isoconfigurational structure types is used. It is shown how these criteria, which include the space group (number), Wyckoff sequence and Pearson symbol, c/a ratio, ranges, ANX formulae and, in certain cases, the necessary elements and forbidden elements, may be used to uniquely identify the representative structure types of the compounds contained in the ICSD database.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The introduction of structure types into the Inorganic Crystal Structure Database ICSD

Allmann¹,

Hinek²

2007

Acta Crystallogr A Found Crystallogr

200

134

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show abstract

“…Nb1 (273 -288 pm) and Nb2 (263 -277 pm) still have CN6, but the gadolinium atoms have CN7 with Gd-Ge distances ranging from 286 to 310 pm. In view of these differences in coordination number, Gd 5 Ge 4 and Gd 2 Nb 3 Ge 4 are, strictly speaking, rather isopointal [53,54] than isotypic. The Nb-Ge distances for the two crystallographically independent niobium atoms in Gd 2 Nb 3 Ge 4 range from 263 to 288 pm, slightly longer than the sum of the covalent radii of 256 pm [52].…”

Section: Crystal Chemistrymentioning

confidence: 99%

Single-crystal Data of Ternary Germanides RE₂Nb₃Ge₄ (RE = Sc, Y, Gd–Er, Lu) and Sc₂Ta₃Ge₄ with Ordered Sm₅Ge₄-type Structure

Reker

Matar

Rodewald

et al. 2013

Zeitschrift Für Naturforschung B

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Small single crystals of the Sm 5 Ge 4 -type (space group Pnma) germanides RE 2 Nb 3 Ge 4 (RE = Sc, Y, Gd-Er, Lu) and Sc 2 Ta 3 Ge 4 were synthesized by arc-melting of the respective elements. The samples were characterized by powder and single-crystal X-ray diffraction. In all structures, except for Sc 2.04 Nb 2.96 Ge 4 and Sc 2.19 Ta 2.81 Ge 4 , the rare earth and niobium atoms show full ordering on the three crystallographically independent samarium sites of the Sm 5 Ge 4 type. Two sites with coordination number 6 are occupied by niobium, while the slightly larger site with coordination number 7 is filled with the rare earth element. Small homogeneity ranges with RE/Nb and RE/Ta mixing can be expected for all compounds. The ordered substitution of two rare earth sites by niobium or tantalum has drastic effects on the coordination number and chemical bonding. This was studied for the pair Y 5 Ge 4 /Y 2 Nb 3 Ge 4 . Electronic structure calculations show larger charge transfer from yttrium to germanium for Y 5 Ge 4 , contrary to Y 2 Nb 3 Ge 4 which shows stronger covalent bonding due to the presence of Nb replacing Y at two sites.

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“…Thus, a simple explanation of the ordering of the elements on the basis of electronegativity trends fails, and the bonding characteristics in the stannide prototype and the magnesium compounds reported here are distinctly different. One should call these phases rather isopointal [16,17] than isotypic. The following crystal chemical discussion relies on the dysprosium compound for which single crystal data are available.…”

Section: Crystal Chemistrymentioning

confidence: 99%

Magnesium-rich Intermetallics RE₃RuMg₇ (RE=Y, Nd, Dy, Ho) – Rows of Condensed Ru@RE_6/2 Octahedra in Magnesium Matrices

Kersting

Rodewald

Schwickert

et al. 2013

Zeitschrift Für Naturforschung B

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The magnesium-rich intermetallic phases RE 3 RuMg 7 (RE = Y, Nd, Dy, Ho) have been synthesized from the elements in sealed niobium ampoules and subsequently characterized by powder X-ray diffraction. The structure of the dysprosium compound was refined on the basis of single-crystal X-ray diffractometer data: Ti 6 Sn 5 type, P6 3 /mmc, a = 1019.1(2), c = 606.76(9) pm, wR2 = 0.0159, 439 F 2 values, 19 variables. The Mg3 site shows a small degree of Mg3/Dy mixing, leading to the composition Dy 3.03 RuMg 6.97 for the investigated crystal. The striking structural motifs in the Dy 3 RuMg 7 structure are rows of face-sharing Ru@Dy 6 octahedra and corner-sharing Mg2@Mg 8 Dy 4 icosahedra. The rows of octahedra form a hexagonal rod-packing, and each rod is enrolled by six rows of the condensed icosahedra. Temperature-dependent magnetic susceptibility measurements of Dy 3 RuMg 7 show Curie-Weiss behavior with an experimental magnetic moment of 10.66(1) µ B per Dy atom. Antiferromagnetic ordering is detected at T N = 27.5(5) K. The 5 K isotherm shows a metamagnetic transition at a critical field of H C = 40 kOe.

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The standardization of inorganic crystal-structure data

Abstract: This paper describes a proposal for a standardized presentation of inorganic crystal-structure data with the aim to recognize identical or nearly identical structures from the similarity of the numerical values of the atom coordinates.

Cited by 255 publications

References 17 publications

The introduction of structure types into the Inorganic Crystal Structure Database ICSD

The introduction of structure types into the Inorganic Crystal Structure Database ICSD

Single-crystal Data of Ternary Germanides RE₂Nb₃Ge₄ (RE = Sc, Y, Gd–Er, Lu) and Sc₂Ta₃Ge₄ with Ordered Sm₅Ge₄-type Structure

Magnesium-rich Intermetallics RE₃RuMg₇ (RE=Y, Nd, Dy, Ho) – Rows of Condensed Ru@RE_6/2 Octahedra in Magnesium Matrices

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The standardization of inorganic crystal-structure data

Abstract: This paper describes a proposal for a standardized presentation of inorganic crystal-structure data with the aim to recognize identical or nearly identical structures from the similarity of the numerical values of the atom coordinates.

Cited by 255 publications

References 17 publications

The introduction of structure types into the Inorganic Crystal Structure Database ICSD

The introduction of structure types into the Inorganic Crystal Structure Database ICSD

Single-crystal Data of Ternary Germanides RE2Nb3Ge4 (RE = Sc, Y, Gd–Er, Lu) and Sc2Ta3Ge4 with Ordered Sm5Ge4-type Structure

Magnesium-rich Intermetallics RE3RuMg7 (RE=Y, Nd, Dy, Ho) – Rows of Condensed Ru@RE6/2 Octahedra in Magnesium Matrices

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About

Single-crystal Data of Ternary Germanides RE₂Nb₃Ge₄ (RE = Sc, Y, Gd–Er, Lu) and Sc₂Ta₃Ge₄ with Ordered Sm₅Ge₄-type Structure

Magnesium-rich Intermetallics RE₃RuMg₇ (RE=Y, Nd, Dy, Ho) – Rows of Condensed Ru@RE_6/2 Octahedra in Magnesium Matrices