Phosphates, Vanadates, Arsenates, Tungstates, and Molybdates GLY 4200 Lab 9 - Fall, 2016
Phosphates, Vanadates, and Arsenates Groups are tetrahedral, with strong bonding with in the group PO43-, VO43-, AsO43- What is the charge on the cation?
Apatite Most important phosphate mineral Major ore of phosphorous Ca5(PO4)3(F,Cl, OH) Occurs in three varieties Fluor Chlor Hydroxy
Phosphates and Radiation Uranium occurs in many phosphate group minerals, making them radioactive The mining of phosphate ores often releases radioactivity into the environment Houses built on or around phosphate gangue material may be plagued by high radon concentrations as a result
Tungstates and Molybdates Cations are quite large W and Mo have nearly identical radii – why? Anionic groups are distorted square planar rather than tetrahedral
Extensive Partial Solid Solution Involves both cations and anionic groups Cation substitution – Wolframite series – complete solid solution FeWO4, Ferberite MnWO4, Huebnerite Wulfenite – PbMoO4 Partial series to Powellite, CaMoO4
Anionic Substitution Partial solid solution CaWO4, Scheelite CaMoO4, Powellite
Text Reference See chapter 17 in the text for more information on phosphates, vanadates, arsenates, tungstates, and molybdates, pp. 405-406 and 425-433