|
Atomistry » Tungsten » Compounds » Potassium Metatungstate | ||
Atomistry » Tungsten » Compounds » Potassium Metatungstate » |
Potassium Metatungstate, K2W4O13
Potassium Metatungstate may be prepared by the following methods:
Potassium metatungstate usually crystallises as the octahydrate, K2W4O13.8H2O, i.e. K6H4[H2(W2O7)6].21H2O, yielding tetragonal octahedra, which effloresce and at 100° C. lose seven-eighths of the water present. Long needle-shaped crystals are also occasionally obtained which are probably identical with the hydrate, K2W4O13.6.5H2O, obtained by Copaux in hexagonal prisms, with axial ratio a:b = 1:0.659, isomorphous with potassium boro- and silico-tungstates. These crystals, like their isomorphs, exhibit dextrorotatory power, [α]D = + 9°. The pentahydrate, K2W4O13.5H2O, is obtained by adding alcohol to a solution of the metatungstate, and warming the mixture until the precipitate redissolves; on cooling the resulting solution, monoclinic prisms separate. These crystals are not efflorescent and are readily soluble in water. Their crystallographic data are a:b:c = 0.5945:1:0.6609; β = 123° 0'. When heated at 100° C. they lose 4 molecular proportions of water. |
Last articlesMg in 4Y52Mg in 4Y30 Mg in 4Y2V Mg in 4Y2X Mg in 4Y2Y Mg in 4Y2U Mg in 4Y2T Mg in 4Y2Q Mg in 4Y2R Mg in 4Y2S |
© Copyright 2008-2020 by atomistry.com | ||
Home | Site Map | Copyright | Contact us | Privacy |