Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

X-ray Crystallography

X-ray Crystallography

The size of the unit cell and the arrangement of atoms in a crystal may be determined from measurements of the diffraction of X-rays by the crystal, termed X-ray crystallography.
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...

$X-ray Diffraction of Biological Samples$ 01:10

X-ray Diffraction of Biological Samples

X-ray diffraction or XRD is an analytical tool that utilizes X-rays to study ordered structures such as crystalline organic and inorganic samples, polycrystalline materials, proteins, carbohydrates, and drugs.
According to Bragg's law, when X-rays strike the sample positioned on a stage, the rays are scattered by the electron clouds around the sample atoms. The X-ray diffraction or scattering is caused by constructive interference of the X-ray waves that reflect off the internal crystal...

Determination of Crystal Structures

Determination of Crystal Structures

In the late 1800s, the revelation that light extended beyond visible wavelengths led to the discovery of X-rays by Wilhelm Roentgen. Recognized as high-energy electromagnetic radiation with short wavelengths, X-rays prompted exploration into their interaction with crystals. Max von Laue proposed in 1912 that the periodic arrangement of atoms, ions, or molecules in crystals would cause them to diffract X-rays, a hypothesis confirmed through experiments with copper sulfate and zinc sulfide...

Lattice Energies of Ionic Crystals

Lattice Energies of Ionic Crystals

Lattice energy represents the energy released when gaseous cations and anions combine to form an ionic solid, reflecting the strength of electrostatic interactions within the crystal. This process is fundamentally governed by Coulombic attraction between oppositely charged ions, where the potential energy varies inversely with the interionic distance and directly with the product of ionic charges. As ions approach one another, the electrostatic energy becomes increasingly negative, indicating a...

Imperfections in Crystal Structure: Stoichiometric Point Defects

Imperfections in Crystal Structure: Stoichiometric Point Defects

Schottky defects arise when some lattice points in a crystal, such as those in NaCl, remain unoccupied, creating lattice vacancies without disturbing the overall electrical neutrality of the crystal. This defect is common in ionic crystals where the positive and negative ions are similar in size, as seen in sodium chloride and cesium chloride. The presence of Schottky defects enables the crystal to conduct electricity to a small extent through an ionic mechanism. Electric fields cause nearby...

Imperfections in Crystal Structure: Non-Stoichiometric Defects

Imperfections in Crystal Structure: Non-Stoichiometric Defects

Non-stoichiometric defects refer to a type of defect in the crystal structure of a compound where the ratio of its constituent elements deviates from the ideal stoichiometric ratio. There are two main types of non-stoichiometric defects: metal excess defects and metal deficiency defects.Metal excess defects occur when there is a slight surplus of metal ions than what is required by the stoichiometric ratio of the compound. For example, heating a sodium chloride crystal in sodium vapor results...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Does the caseload of the pathologist influence the minimum and extended data set of pathology variables reported for rectal adenocarcinoma?

Colorectal disease : the official journal of the Association of Coloproctology of Great Britain and Ireland·2013

Same author

Robert Thompson Leiper FRS (1881-1969).

Journal of medical biography·2010

Same author

Special Discussion on the Epidemiology of Cerebrospinal Meningitis.

Proceedings of the Royal Society of Medicine·2009

Same author

What is the incidence of leg weakness after ilio-inguinal block in children?

Paediatric anaesthesia·2000

Same author

Nondestructive Angle-resolved X-ray Depth Profiling: Interpretation of Angle-resolved Profiles Using a Monte Carlo Approach.

Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada·2000

Same author

Advances in SEM-based diffraction studies of defects and strains in semiconductors

Journal of electron microscopy·2000

Search research articles

Related Experiment Video

Updated: Jul 17, 2026

$X-ray Powder Diffraction in Conservation Science: Towards Routine Crystal Structure Determination of Corrosion Products on Heritage Art Objects$

X-ray Powder Diffraction in Conservation Science: Towards Routine Crystal Structure Determination of Corrosion Products on Heritage Art Objects

Published on: June 8, 2016

Modulated structure of La2Co1.7 from neutron and X-ray diffraction data

Dusek¹, Chapuis, Schobinger-Papamantellos

¹Universite de Lausanne, Institut de Cristallographie, BSP Dorigny, CH-1015 Lausanne, Switzerland, and Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, 182 21 Praha 8, Czech Republic. dusek@fzu.cz.

Acta Crystallographica. Section B, Structural Science

|December 2, 2000

Summary

This study reveals that cobalt atoms in La(2)Co(1.7) crystals exhibit incommensurate modulation, deviating from ideal hexagonal close packing. The crystal structure is described as a composite system with modulated lanthanum atoms.

More Related Videos

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses

Published on: June 7, 2018

Molten-Salt Synthesis of Complex Metal Oxide Nanoparticles

Molten-Salt Synthesis of Complex Metal Oxide Nanoparticles

Published on: October 27, 2018

Related Experiment Videos

Last Updated: Jul 17, 2026

$X-ray Powder Diffraction in Conservation Science: Towards Routine Crystal Structure Determination of Corrosion Products on Heritage Art Objects$

X-ray Powder Diffraction in Conservation Science: Towards Routine Crystal Structure Determination of Corrosion Products on Heritage Art Objects

Published on: June 8, 2016

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses

Published on: June 7, 2018

Molten-Salt Synthesis of Complex Metal Oxide Nanoparticles

Molten-Salt Synthesis of Complex Metal Oxide Nanoparticles

Published on: October 27, 2018

Area of Science:

Solid-state chemistry
Crystallography
Materials science

Background:

Understanding the atomic arrangement in intermetallic compounds is crucial for predicting their properties.
Lanthanum cobalt (La-Co) compounds are of interest due to their potential magnetic and electronic applications.
Previous studies suggest complex structural behaviors in related systems.

Purpose of the Study:

To elucidate the crystal structure of La(2)Co(1.7) using advanced diffraction techniques.
To investigate the nature of atomic modulations and their impact on the crystal structure.
To determine the precise chemical composition and refine structural models.

Main Methods:

Single-crystal neutron diffraction at low and room temperatures.
Single-crystal X-ray diffraction at room temperature.
Analysis using Laue white-beam and CCD detectors.
Indexing and structure solution in superspace groups.

Main Results:

The average structure of La(2)Co(1.7) is hexagonal (P6(3)/mmc).
Satellite reflections indicate a 3+1 dimensional incommensurately modulated structure.
Cobalt atoms display positional disorder due to steric constraints, adopting a non-commensurate periodicity with lanthanum.
Refined models include a sawtooth function and a composite system, yielding a composition of La(2)Co(1.8(1)).

Conclusions:

The La(2)Co(1.7) crystal exhibits an incommensurately modulated structure.
Cobalt atoms are not precisely located in ideal octahedral sites, leading to a different periodicity than lanthanum.
The structure can be described as a composite system with modulated lanthanum and non-periodically displaced cobalt atoms.