Vlasovite is a rare inosilicate (chain silicate) mineral with sodium and zirconium , with the chemical formula Na 2 ZrSi 4 O 11 . It was discovered in 1961 at Vavnbed Mountain in the Lovozero Massif , in the Northern Region of Russia. The researchers who first identified it, R P Tikhonenkova and M E Kazakova, named it for Kuzma Aleksevich Vlasov (1905–1964), a Russian mineralogist and geochemist who studied the Lovozero massif, and who was the founder of the Institute of Mineralogy, Geochemistry, and Crystal Chemistry of Rare Elements, Moscow, Russia.
26-489: At temperatures below 29 °C the stable form of vlasovite is triclinic 1 , space group P 1 . Above 29 °C the stable form is monoclinic 2/m. Most sources simply give it as monoclinic 2/m, space group C2/c. The silicate part of the structure is a chain composed of rings of four SiO 4 tetrahedra linked by sharing a corner oxygen to form a chain of composition [Si 4 O 11 ]. These chains of tetrahedra link together with zirconium , Zr, octahedra to form
52-562: A framework with channels extending along [001] , parallel to the c crystal axis . The channels contain the sodium , Na, atoms. The unit cell parameters are a = 11 Å, b = 10 Å, c = 8.5 Å and β = 100°, with 4 formula units per unit cell (Z = 4). More accurate values are given by various sources as follows. For the monoclinic cell: For the triclinic cell: Vlasovite is colorless, pink, pale brown or silvery in reflected light and colourless in transmitted light. The border zones of large grains are light brown due to dust-like inclusions. It
78-474: A single crystal, but are poly-crystalline in nature (they exist as an aggregate of small crystals with different orientations). As such, powder diffraction techniques, which take diffraction patterns of samples with a large number of crystals, play an important role in structural determination. Other physical properties are also linked to crystallography. For example, the minerals in clay form small, flat, platelike structures. Clay can be easily deformed because
104-596: Is a broad topic, and many of its subareas, such as X-ray crystallography , are themselves important scientific topics. Crystallography ranges from the fundamentals of crystal structure to the mathematics of crystal geometry , including those that are not periodic or quasicrystals . At the atomic scale it can involve the use of X-ray diffraction to produce experimental data that the tools of X-ray crystallography can convert into detailed positions of atoms, and sometimes electron density. At larger scales it includes experimental tools such as orientational imaging to examine
130-781: Is a freely accessible repository for the structures of proteins and other biological macromolecules. Computer programs such as RasMol , Pymol or VMD can be used to visualize biological molecular structures. Neutron crystallography is often used to help refine structures obtained by X-ray methods or to solve a specific bond; the methods are often viewed as complementary, as X-rays are sensitive to electron positions and scatter most strongly off heavy atoms, while neutrons are sensitive to nucleus positions and scatter strongly even off many light isotopes, including hydrogen and deuterium. Electron diffraction has been used to determine some protein structures, most notably membrane proteins and viral capsids . The International Tables for Crystallography
156-656: Is a late phase in nepheline syenite and syenitic pegmatites . At Ascension Island it is found in miarolitic cavities in ejected blocks of peralkaline granite (Peralkaline rocks are deficient in aluminium but have sodium and potassium in excess of the amount needed to form feldspar). At the Lovozero Massif in Russia it is formed in areas of rock rich in microcline and albite in the contact zone between pegmatites and fenites (metasomatic rocks composed of alkaline feldspar, sodic pyroxene and alkaline amphibole), by
182-404: Is an eight-book series that outlines the standard notations for formatting, describing and testing crystals. The series contains books that covers analysis methods and the mathematical procedures for determining organic structure through x-ray crystallography, electron diffraction, and neutron diffraction. The International tables are focused on procedures, techniques and descriptions and do not list
208-435: Is crucial in various fields, including metallurgy, geology, and materials science. Advancements in crystallographic techniques, such as electron diffraction and X-ray crystallography, continue to expand our understanding of material behavior at the atomic level. In another example, iron transforms from a body-centered cubic (bcc) structure called ferrite to a face-centered cubic (fcc) structure called austenite when it
234-404: Is heated. The fcc structure is a close-packed structure unlike the bcc structure; thus the volume of the iron decreases when this transformation occurs. Crystallography is useful in phase identification. When manufacturing or using a material, it is generally desirable to know what compounds and what phases are present in the material, as their composition, structure and proportions will influence
260-476: Is the primary method for determining the molecular conformations of biological macromolecules , particularly protein and nucleic acids such as DNA and RNA . The double-helical structure of DNA was deduced from crystallographic data. The first crystal structure of a macromolecule was solved in 1958, a three-dimensional model of the myoglobin molecule obtained by X-ray analysis. The Protein Data Bank (PDB)
286-560: Is transparent to translucent, with a white streak and greasy luster , vitreous to pearly on cleavage surfaces. The refractive indices are N x = 1.607, N y = 1.623 and N z = 1.628, similar to those of muscovite . Vlasovite is not fluorescent , but altered portions of the material fluoresce orange-yellow under both long-wave and short-wave ultra-violet illumination. Crystals have been found up to 15 cm long, but vlasovite occurs more commonly as irregularly shaped grains and aggregates. It shows distinct cleavage parallel to
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#1732783884364312-470: Is used by materials scientists to characterize different materials. In single crystals, the effects of the crystalline arrangement of atoms is often easy to see macroscopically because the natural shapes of crystals reflect the atomic structure. In addition, physical properties are often controlled by crystalline defects. The understanding of crystal structures is an important prerequisite for understanding crystallographic defects . Most materials do not occur as
338-1092: The diffraction patterns of a sample targeted by a beam of some type. X-rays are most commonly used; other beams used include electrons or neutrons . Crystallographers often explicitly state the type of beam used, as in the terms X-ray diffraction , neutron diffraction and electron diffraction . These three types of radiation interact with the specimen in different ways. It is hard to focus x-rays or neutrons, but since electrons are charged they can be focused and are used in electron microscope to produce magnified images. There are many ways that transmission electron microscopy and related techniques such as scanning transmission electron microscopy , high-resolution electron microscopy can be used to obtain images with in many cases atomic resolution from which crystallographic information can be obtained. There are also other methods such as low-energy electron diffraction , low-energy electron microscopy and reflection high-energy electron diffraction which can be used to obtain crystallographic information about surfaces. Crystallography
364-421: The symmetry of the crystal in question. The position in 3D space of each crystal face is plotted on a stereographic net such as a Wulff net or Lambert net . The pole to each face is plotted on the net. Each point is labelled with its Miller index . The final plot allows the symmetry of the crystal to be established. The discovery of X-rays and electrons in the last decade of the 19th century enabled
390-401: The triclinic (or anorthic ) crystal system is one of the seven crystal systems . A crystal system is described by three basis vectors . In the triclinic system, the crystal is described by vectors of unequal length, as in the orthorhombic system. In addition, the angles between these vectors must all be different and may not include 90°. The triclinic lattice is the least symmetric of
416-552: The 14 three-dimensional Bravais lattices . It has (itself) the minimum symmetry all lattices have: points of inversion at each lattice point and at 7 more points for each lattice point: at the midpoints of the edges and the faces, and at the center points. It is the only lattice type that itself has no mirror planes. The triclinic crystal system class names, examples, Schönflies notation , Hermann-Mauguin notation , point groups, International Tables for Crystallography space group number, orbifold , type, and space groups are listed in
442-1119: The South Atlantic Ocean, the Kipawa Complex , Villedieu Township, Quebec and the Strange Lake Complex in Labrador . Type material is conserved for reference in two locations in Russia, the Saint Petersburg Mining Institute and the Fersman Mineralogical Museum in Moscow, and also in France, at the National School of Mines in Paris. JMol: http://rruff.geo.arizona.edu/AMS/viewJmol.php?id=06176 Triclinic crystal system In crystallography ,
468-601: The determination of crystal structures on the atomic scale, which brought about the modern era of crystallography. The first X-ray diffraction experiment was conducted in 1912 by Max von Laue , while electron diffraction was first realized in 1927 in the Davisson–Germer experiment and parallel work by George Paget Thomson and Alexander Reid. These developed into the two main branches of crystallography, X-ray crystallography and electron diffraction. The quality and throughput of solving crystal structures greatly improved in
494-398: The material's properties. Each phase has a characteristic arrangement of atoms. X-ray or neutron diffraction can be used to identify which structures are present in the material, and thus which compounds are present. Crystallography covers the enumeration of the symmetry patterns which can be formed by atoms in a crystal and for this reason is related to group theory . X-ray crystallography
520-432: The plane containing the a and c crystal axes , and this plane can also be a twin plane , although twinning is uncommon. Vlasovite is a brittle mineral, with an irregular to conchoidal fracture , hardness 6 and specific gravity 2.97. It is nearly insoluble in hydrochloric acid HCl and nitric acid HNO 3 , but it dissolves easily in a mixture of hydrofluoric acid , HF, and sulfuric acid H 2 SO 4 . Vlasovite
546-421: The platelike particles can slip along each other in the plane of the plates, yet remain strongly connected in the direction perpendicular to the plates. Such mechanisms can be studied by crystallographic texture measurements. Crystallographic studies help elucidate the relationship between a material's structure and its properties, aiding in developing new materials with tailored characteristics. This understanding
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#1732783884364572-467: The relative orientations at the grain boundary in materials. Crystallography plays a key role in many areas of biology, chemistry, and physics, as well new developments in these fields. Before the 20th century, the study of crystals was based on physical measurements of their geometry using a goniometer . This involved measuring the angles of crystal faces relative to each other and to theoretical reference axes (crystallographic axes), and establishing
598-483: The replacement of eudialyte . Associated minerals include arfvedsonite , aegirine , apatite and fluorite , in addition to microcline, albite and eudialyte. The type locality is the Vavnbed Mountain, Lovozero Massif, Kola Peninsula, Murmanskaja Oblast', Northern Region, Russia, which is also a good locality for zircon crystals. Other localities for vlasovite include the volcanic Ascension Island, in
624-557: The second half of the 20th century, with the developments of customized instruments and phasing algorithms . Nowadays, crystallography is an interdisciplinary field , supporting theoretical and experimental discoveries in various domains. Modern-day scientific instruments for crystallography vary from laboratory-sized equipment, such as diffractometers and electron microscopes , to dedicated large facilities, such as photoinjectors , synchrotron light sources and free-electron lasers . Crystallographic methods depend mainly on analysis of
650-609: The study of molecular and crystalline structure and properties. The word crystallography is derived from the Ancient Greek word κρύσταλλος ( krústallos ; "clear ice, rock-crystal"), and γράφειν ( gráphein ; "to write"). In July 2012, the United Nations recognised the importance of the science of crystallography by proclaiming 2014 the International Year of Crystallography. Crystallography
676-414: The table below. There are a total of 2 space groups. With each only one space group is associated. Pinacoidal is also known as triclinic normal. Pedial is also triclinic hemihedral. Mineral examples include plagioclase , microcline , rhodonite , turquoise , wollastonite and amblygonite , all in triclinic normal ( 1 ). Crystallography Crystallography is the branch of science devoted to
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