GEOS 306 Midterm: GEOS 306 University of Arizona Midterm 1 2010
31 Jan 2019
School
Department
Course
Professor
Document Summary
, fe3+: (10 pts) derive the radius-ratio rule parameter (r. = . 155) for an trigonal planar 3- coordinated cation. Draw a picture and carefully label everything so that your answer can be evaluated properly. A: (15 pts) list 7 common types of bonding found in minerals along with a short description and an example of each, a) (5 pts) suppose the illustrated figures represent closest-packed arrangements of anions. Identify the different locations where cations could be coordinated with 2, 3, Bonus point: name the mineral: (5 pts) the mineral stishovite is the high-pressure polymorph of silica found deep within the earth, or at meteorite impact sites. It is characterized as consisting of sio6 polyhedra, rather than sio4 as for the other silica polymorphs. Using a rationale based on pauling"s radius-ratio principles, explain why the si goes from 4-coordinated in quartz to 6-coordinated in stishovite.
