GEOL 114 Lecture Notes - Lecture 9: Molecular Geometry, Epidote, Covalent Bond
Document Summary
Minerals: solid, orderly arrangement of atoms called a crystal structure. This determines the physical properties of the mineral. Consist of covalent or ionic bonds, or sometimes both. Coordination number: number of anions surrounding each cation. Formed of oxygen and silicon and have a coordinate number of 4 (meaning there are 4 oxygen atoms per silicon atom). O and si form covalent bond, complex form ionic bonds with other atoms (sio4) Varying geometry and what atoms are interacting will form different minerals. Geometry examples: island silicates: isolated tetrahedrons compose topaz, garnet, or olivine (argued to be the most important mineral on earth, bow-tie silicates: shares one oxygen atom with other tetrahedral. Forms epidote: ring silicates: two oxygen atoms are shared between tetrahedron. Examples include emeralds or aquamarine (types of beryl: single chain silicates: two oxygen atoms shared to form chains of tetrahedral. Jade is in example (type of pyroxene: double chain silicates: chains combing.
