Beryllium tellurate has the molecular formula of
BeTeO4 and the molecular weight of 200.61 grams per
mole. Its solubility is 6.72 g/100 ml at 20°C. It can
be prepared by the solid-state reaction of TeO3 and BeO:
BeO+ TeO3 ? BeTeO4
This is the tetragonal composition. It can also be
formed in the same manner by solid-state reaction of
telluric acid:
BeO(solid)+ H2TeO4(solid) ? BeTeO4(solid)+H2O(gas)
Telluric acid is soluble in water and produces
Te(OH)4O2-
anions in solutions. If beryllium chloride
is added, the product is a tetrahydrate:
BeCl2(aq)+H2Te(OH)4(aq) ? {Be(OH)}2Te(OH)4
where the tellurate complex changes from an octahedral
to a tetrahedral configuration. Although the chemistry
of beryllium tellurate was studied earlier, it has
received no attention in the current literature. According
to Topsoe (1872), beryllium tellurate crystallizes in the
rhombohedral system with a ratio of lattice parameters
a:b:c = 1:0.9602:0.9027. More recently, this compound
has been said to be cubic and have a structure very similar
to spinel, MgAl2O4. A compound having the molecular
formula of Be4TeO7 is said to be isomorphous to spinel
as well.
