EARTHSC 1108 Lecture Notes - Lecture 7: Ionic Bonding, Ion, Orthorhombic Crystal System
5 Apr 2016
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Document Summary
Atomic bonding-ions from when atoms lose electrons (cations-positive) or gain electrons (anions-negative) The size of the anions determines the size of the cation that can occupy the site created by the anions. 1) tetrahedron: central cation surrounded by 4 anions at corners, forms triangular pyramid. 2) octahedron: central cation surrounded by 6 anions , forms a double pyramid. 3) cube: central cation is surrounded by 8 anions, forms a cube. 1) silicon: oxygen tetrahedra linked by sharing oxygen atoms (at corners) between two adjacent tetrahedra. 1) sharing edges: two adjacent oxygens are shared. 2) sharing faces: three adjacent oxygens are shared. Minerals with identical chemical formulas, but the atoms are arranged differently. Arrangement of atoms depends on the temp and pressure conditions that the mineral formed under. Some minerals show crystals faces and others don"t, but all are crystalline (orderly arrangement of atoms)
