Lecture 1 - Introduction to Crystallography - PDF

Lecture 1 (26/11/2024) Introduction to Crystallography 11/26/2024 Assistant lect. Shleer Burhan 1  Assistant lect. Shleer Burhan (Rocks & Minerals) [email protected] 11/26/2024 Assistant lect...

Lecture 1 (26/11/2024) Introduction to Crystallography 11/26/2024 Assistant lect. Shleer Burhan 1  Assistant lect. Shleer Burhan (Rocks & Minerals) [email protected] 11/26/2024 Assistant lect. Shleer Burhan 2  Mineralogy: Mineral Science 2025-2024 First Simster Second Semister Crystallography Mineralogy 11/26/2024 Assistant lect. Shleer Burhan 3  Basic building of Human Developments: Solid universe : rail way, car , electrcity, Earth, Moon, Planet, comunication , bulding, meteorites Agricaulture National Econmoic : Statigeic minerals, Gold, Sliver , PGE, Rocks: REE, Cu, Fe, Uranium Ignouse, COURSE Metamorphic , DESCRIPTION Sedimentary Earth history and Ages : Zircon Gemstone : Diamond 11/26/2024 Assistant lect. Shleer Burhan 4  Crystallography Mineralogy COURSE OVERVIEW Science of determining the arrangement of atoms in crystalline solids is the study of naturally occurring crystalline substances 11/26/2024 Assistant lect. Shleer Burhan 5   What are minerals, and how are  What is crystal? they different from rock?  What is the basic of a mineral?  What are the major parts of crystals?  What are the some of the physical and chemical properties of minerals?  What is the Crystal symmetry and crystal form? COURSE OBJECTIVE:  How can these properties be used to distinguish one mineral from another?  What is the Classification of crystal according to system?  What are the genesis and origin of the minerals?  What is the most abundant mineral group?  What are the important of minerals? 11/26/2024 Assistant lect. Shleer Burhan 6  2nd Exam Lec1: Introduction Lec13: The 32 Point Groups (Crystal Classes) Lec2: Basics of Crystallography Lec12: The 14 Bravais Lattices Lec3: Polyhedron & Crystallographic axes An Outline of the Lec11: Crystal Lattice Lec4 : The crystal system Crystallography Lec10: Crystal Projection (First semester) Lec9: Crystal Habit Lec5: Elements of symmetry Lec8: Miller Indices Lec6: Crystal Form Lec7: Axial Ratio & Faces intercepts Ist Exam 11/26/2024 Assistant lect. Shleer Burhan 7  Basics of Crystallography DEFINITION CHARACTERISTICS 11/26/2024 Assistant lect. Shleer Burhan 8  Why we study Crystallography? It is useful for the identification of minerals. The later are chemical substances formed under natural conditions and have crystal forms. 11/26/2024 Assistant lect. Shleer Burhan  Physical substance in general, as distinct from mind and spirit; (in physics) that which occupies space and possesses rest mass, especially as distinct from energy Matter Structure Composition States Gas Solid Crystalline NON Ions Liquid Crystalline Chemical Cation vs bonds Anions 11/26/2024 Assistant lect. Shleer Burhan 10  Mineral Criteria 1. Solid 6. Stable at 25 C° 2. Natural 5. Crystalline 3. Inorganic 4. Chemical formula Assistant lect. Shleer Burhan 11 11/26/2024  Definition Why it is important Science of study crystal 1. Identification of minerals 2. How to produce a mineral Crystallography Geometrical Structural Crystallography crystallography Study internal part of crystals Study external shape of crystals 11/26/2024 Assistant lect. Shleer Burhan 12  It is a branch of science in which the Crystallography geometry internal structure and physical properties of crystalline materials are studied. It is a natural solid body, has 1regular Crystal atomic arrangement and 2certain chemical composition, 3bounded by plane surfaces. It is the process of forming a crystalline Crystallization structure from a fluid or from materials dissolved in a fluid(More rarely, crystals may be deposited directly from gas). 11/26/2024 Assistant lect. Shleer Burhan 13  1. Chemical composition Cation: Anions : a Negatively charged ion a positively charged ion E>P P>E How do atoms fit together to make crystals with different shape? 11/26/2024 Assistant lect. Shleer Burhan 14  The arrangement of atoms depend one Elements Charge + or - is a link between ions in a crystal Bonds Charge is a characteristic of atom which expresses either loss or gain of electrons. It shows the excess or deficiency of electrons. It can be positive if an atom loses electron and it can be negative if it accepts electrons. Coordination number Is the number of ions or atoms that immediately surround an atom or ion 11/26/2024 Assistant lect. Shleer Burhan 15  Elements 11/26/2024 Assistant lect. Shleer Burhan 16  Bonds A chemical bond is a permanent attraction between atoms, ions or molecules that enables Ionic the formation of chemical compounds ( Mineral or crystal) Metallic Covaleant Ionic bonding is a type of chemical bonding that involves the electrostatic A covalent bond, also called a Metallic bonding is a type of molecular bond, is a chemical chemical bonding that rises from attraction between The electrostatic attractive force oppositely charged ions bond that involves the between conduction electrons sharing of electron pairs and positively charged metal between atoms. ions. 11/26/2024 Assistant lect. Shleer Burhan 17  Coordination number Rx is the radius of the cation, and Rz is the radius of the surrounding anions Relative size Rx/Rz Same size Relative size Rx/Rz = 1 Rx/Rz ≤ 1 CN= 12 Hexagonal closest Cubic closest packing packing ABC ABC ABAB Assistant lect. Shleer Burhan 18 11/26/2024  In this case, the maximum number of atoms that be coordinated around any Same size individual is 12. We call this 12-fold Rx/Rz = 1 coordination. There are two ways that atoms can be packed in 12-fold coordination. 11/26/2024 Assistant lect. Shleer Burhan 19  Relative size Rx/Rz = < 0.155 CN.2 Linear Relative size Rx/Rz = 1 to 0.732 Relative size CN=8 Rx/Rz = 0.225 to 0.155 Cubic CN.3 Triangle Relative size Rx/Rz ≤ 1 Relative size Relative size Rx/Rz = 0.732 to 0.414 Rx/Rz = 0.414 to 0.225 CN.6 CN.4 Octahedron Tetrahedron 11/26/2024 Assistant lect. Shleer Burhan 20  Crystal Disordered Ordered (Mineraloid) 11/26/2024 Assistant lect. Shleer Burhan 21 11/26/2024 Assistant lect. Shleer Burhan  Anisotropy Symmetry Self-faceting ability Properties of Crystalline Substances Solidity 11/26/2024 Assistant lect. Shleer Burhan 23  How the Crystal Is formed Example: How Salt Crystals form Salt molecule 11/26/2024 Assistant lect. Shleer Burhan 24  + = Salt solution Salt molecule Water molecule Evaporation Salt crystals 25 11/26/2024 Assistant lect. Shleer Burhan  Crystal Symmetry Crystal Form or habit Faces Crystal Parts Crystal Axes Edge Interfacial Angle Solid Angle 11/26/2024 Assistant lect. Shleer Burhan 26  Faces Crystals are bounded by surfaces which are usually plane. These surfaces are called faces. 11/26/2024 Assistant lect. Shleer Burhan 27  Type of Faces Like Faces Un Like Faces Crystal consist of more than one shape all faces have the same shape 11/26/2024 Assistant lect. Shleer Burhan 28  Edge It is formed by intersection of two adjacent faces 11/26/2024 Assistant lect. Shleer Burhan 29  Solid Angle It is a point which formed by intersection of three or more adjacent faces. 11/26/2024 Assistant lect. Shleer Burhan 30  Interfacial Angle The angle between any two adjacent faces of a crystal is termed the interfacial angle, and is, in crystallography, the angle between the normals to the two faces. 11/26/2024 Assistant lect. Shleer Burhan 31  How to measure interfacial angle Reflection Goniometer Contact Goniometer 11/26/2024 Assistant lect. Shleer Burhan 32  Combination of Crystal parts Edge Definition: A polyhedron is a solid in three dimensions that consists of straight edges and faces. Polyhedron Faces Solid Angle 11/26/2024 Assistant lect. Shleer Burhan 33  Polyhedron Tetrahedron Icosahedron Octahedron Dodecahedron Cube Points 11/26/2024 Assistant lect. Shleer Burhan 34  Symmetry Definition : similar parts facing each other or around an axis  is a group of crystal faces, all FORM having the same relationship to the elements of symmetry of a given crystal system. The Crystals are defined by the lengths and angles between crystallographic axes. Crystal Axes Generally, there are three axes, termed a, b, and c and three inter-axial angles alpha, beta, and gamma, 11/26/2024 Assistant lect. Shleer Burhan 35