Crystal Chemistry Flashcards
The study of atomic structure, physical properties, and chemical composition of crystalline material.
Crystal Chemistry
Most abundant elements from 1 to 8
Oxygen, Silicon, Aluminum, Iron, Calcium, Sodium, Potassium, Magnesium
Minute building blocks of all matter, including minerals, that cannot be chemically split.
Atom
A small, positively-charged central region of an atom.
Nucleus
Positively-charged particle
Proton
Neutrally-charged particle
Neutron
Negatively-charged particle
Electron
A vastly larger, mostly “empty” region of an atom where electrons move in orbitals around the nucleus.
Electron cloud
Electrons found on the outermost region in the electron cloud that is free to interact with other atoms to form chemical bonds.
Valence Electron
A substance whose atoms are characterized by having the same number of atoms.
Element
Atoms of the same element that possess different atomic mass numbers.
Isotope
Isotopes that possess stable nuclei, retaining the same number of protons and neutrons over time.
Stable Isotopes
Isotopes that possess unstable nuclei, whose nuclear configuration tend to be spontaneously transformed by radioactive decay.
Radioactive Isotopes
Charged Atoms crave?
Stability
Explain octet rule
Atoms tend to gain or lose or share electrons until they are surrounded by eight valence electrons.
The transfer or sharing of electrons to attain the complete eight valence electrons
Chemical Bond
Atoms that possess an electrical charge due to the loss or gain of an electron.
Ions
Positively charged ions
Cation
Negatively charged ions
Anion
5 types of bonding
Ionic Bond
Covalent Bond
Metallic Bond
Van der Waals Bond
Hydrogen Bond
One atom gives up one or more of its valence electrons to another to form ions.
Ionic Bonding
Mineral Characteristics of Ionic Bonding and give a mineral
Variable Hardness
Brittle at room temp
Quite soluble in polar substances
Intermediate melting temp
Translucent to transparent
Mineral: Halite
A chemical bond formed by the sharing of a pair of electrons between atoms.
Covalent Bonding
Mineral Characteristics of Covalent Bonding and give a mineral
Hard and brittle at room temp
Insoluble in polar substances
Crystallize from melts
Mod to high melting temp
Translucent to transparent
Mineral: Diamond
Valence electrons shared between atoms are free to move from one atom to another, accounting for a high electrical conductivity
Metallic Bonding
Mineral Characteristics of Metallic Bonding and give a mineral
Fairly soft to mod. hard
Plastic, malleable and ductile.
Excellent electrical and thermal conductors
High specific gravity
Opaque
Mineral: Gold
Forces include attraction and repulsions between atoms, molecules, and surfaces, created by weak bonding of oppositely depolarized electron clouds, and commonly occurs around covalently bonded elements.
Van Der Waals Bonding
Mineral Characteristics of Van Der Waals Bonding and give a mineral
Soft.
Poor conductors.
Low melting points.
Low crystal symmetry.
Mineral: Graphite
Weak bond between 2 molecules resulting from an electrostatic
attraction between a proton in one, and an electron in another.
Hydrogen Bonding
Mineral Characteristics of Hydrogen Bonding and give a mineral
Occurs in hydrated or hydroxyl minerals.
Mineral: Ice
Rank the 5 types of bonding on strength
Covalent
Ionic
Metallic
Hydrogen
Van der Waals
The process of one ion replacing another ion due to its
availability in the environment while the mineral is forming, and occurs due to an ion having a similar size and a similar charge.
Atomic Substitution
Explain Simple Complete Substitution and give a mineral
A type of substitution that exists when two or more ions of
similar radius and the same charge substitute for one another in a coordination site in any proportions. - Olivine
Explain Coupled Ionic Substitution and give a mineral
A type of substitution that involves the simultaneous substitution of ions of different charges in two different structural sites.
Plagioclase Feldspar
Explain Limited Ionic Substitution and give an example
A type of substitution that exists between end-member components of a solid solution series due to ions of substantially different sizes limiting the amount of substitution.
Calcite to Magnesite
A branch of mineralogy that studies the long-range order or
crystal structure of crystalline substances.
Crystallography
Flat surfaces enclosing a crystal that are formed when enclosed minerals stop growing.
Crystal Faces
Smallest unit of pattern, that when repeated by a set of symmetry operations, will generate the long-range pattern characteristic
of the crystal; Set of atoms arranged in a specific way.
Motif
A point used to represent any motif
Node
The repetition of these fundamental units of pattern with long-range order.
Symmetry Operations
2 types of symmetry operations
Simple symmetry
compound symmetry
A periodic repetition of nodes in a systematic, linear displacement.
Translation
A specific length and direction of systematic displacement by
which the pattern repeats.
Unit Translation Vector (t)
A form of translation defined by two-unit translation vectors:
ta and tb, or t1 and t2
Two-dimension 2D
is a two-dimensional array of pattern of nodes generated by the two-dimensional translation. (also called Plane Mesh)
Plane Lattice
A form of translation defined by two-unit translation
vectors: ta , tb and t1 , t2 and t3.
Three-dimension Translation
A three dimensional array of pattern of
nodes generated by the two dimensional translation.
Space Lattice
The resulting array of motifs of crystalline substances.
Crystal Lattice
A perfectly repetition of patterns in a complete 360°rotation around an axis of rotation.
Rotation (n)
An imaginary line or axis where a pattern of nodes rotate around.
Axis of Rotation
A form of symmetry operation in which every component of a pattern is repeated by reflection through a mirror plane.
Reflection (m)
An imaginary line or axis where a pattern of nodes rotate around.
Mirror Plane
The repetition of motifs by inverting them through a center called center of inversion.
Inversion (i)
A point where the “image” of the motif is inverted through.
Center of Inversion
The combination of translation with reflection across a mirror plane, producing a glide plane.
Glide Reflection
The combination of translation with reflection across a mirror plane, producing a glide plane.
Rotoinversion (n-)
The combination of translation parallel to an axis with rotation about the axis.
Screw Rotation (na)
Two-dimensional motifs that are consistent with the generation of long-range, two dimensional arrays.
Plane Point Group
The smallest units of plane lattice which contain at least one node and the unit translation vectors. It contains all the information necessary to produce the only larger two-dimensional pattern.
Unit Mesh
A set of 17 plane lattice groups formed through the combination of the 10 plane point groups and 5 unit meshes.
Plane Lattice Groups
Three-dimensional equivalents of two-dimensional equivalents plane point groups.
Space Point Group
The 32 three-dimensional motif symmetries defined by the arrangement of the space point groups.
Crystal Classes
A set of imaginary orientations used to describe the direction of a crystal’s propagation.
Crystallographic Axes
A classification of minerals based on the relative measurement of their unit edges (a, b, and c), and the angles between them (α, β, and γ).
Crystal Systems
6 Crystal Systems
Isometric/Cubic
Tetragonal
Orthorhombic
Monoclinic
Triclinic
Hexagonal
Rhombohedral/Trigonal
