Borotellurites are chemical mixed anion compounds that contain any kind of borate and tellurite ions bound together via oxygen. They are distinct from borotellurates in which tellurium is in the +6 oxidation state. There are also analogous boroselenites, with selenium instead of tellurium also in the +4 oxidation state. Borotellurites are colourless and many are birefringent.
List chemmwcrystal system space groupunit cellvolumedensitycommentsreferencesYTeBO5307.32orthorhombicPbcaa=10.458 b=6.5842 c=11.092 Z=8763.755.345birefringence 0.08@546 nmK3BaTeB7O15monoclinicP21/ca=8.979 b=6.303 c=25.869 β=98.095°transparent above 235 nm; birefringence 0.03@1064 nmRb3BaTeB7O15monoclinicP21/na=9.102 b=6.409 c=25.794 β=97.278°LaTeBO5357.32orthorhombicPbcaa=10.8220 b=6.9216 c=11.5812 Z=8867.505.472colourless; large birefringenceβ-LaTeBO5357.32monoclinicP21/ca=16.7501 b=7.1820 c=8.3492 β=104.124° Z=4974.044.873birefringence 0.134@546 nmGdTeBO5375.66orthorhombicPbcaa=10.5878 b=6.6574 c=11.2141 Z=8790.456.313birefringence 0.074@546 nmTbTeBO5373.33orthorhombicPbcaa=10.5343 b=6.6235 c=11.153 Z=8778.176.441PbTeB4O9triclinicP-1a=6.5740 b=6.7445 c=9.8903 α=70.105° β=78.877° γ=61.726°birefringence 0.099@1064 nm
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