Английская Википедия:Borotellurate

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The borotellurates are heteropoly anion compounds which have tellurate groups attached to boron atoms. The ratio of tellurate to borate reflects the degree of condensation. In [TeO4(BO3)2]8- the anions are linked into a chain.[1] In [TeO2(BO3)4]10− the structure is zero dimensional with isolated anions. These arrangements of oxygen around boron and tellurium can have forms resembling silicates. The first borotellurates to be discovered were the mixed sodium rare earth compounds in 2015.[1]

The tellurate is of the form TeO6 in an octahedral arrangement. The borate is in the form BO3, with two oxygen atoms shared with two tellurate TeO6 groups.[1]

Related compounds include boroantimonates, galloborates, borogermanates, borophosphates, boroselenates, boroselenites, and borosulfates.[2]

Formation

Borotellurates are formed by heating boric acid, and tellurium dioxide, with metal carbonates or oxides at over 800 °C.[1] Lower temperatures can be used with a flux like potassium carbonate.[3]

Reactions

When heated to around 800 °C the borotellurates decompose by emitting TeO3 vapour and form a metal borate[1] or metal tellurite.[4]

List

chem mw crystal system space group unit cell Å volume density comment references
Rb3BaTeB7O15 837.02 monoclinic P21/n a=9.102 b=6.409 c=25.794 β=97.278 Z=4 1492.6 3.725 actually this is a tellurite [5]
Sr5TeO2(BO3)4 832.94 tetragonal P4/mnc a= 7.6005 c=10.401 600.82 4.604 colourless [6]
Na2Y2TeO4(BO3)2 533.02 monoclinic P21/c a=6.3073, b=9.9279, c=6.7219; β=104.26°; Z=2 407.94 4.339 [1]
barium tellurium borate Ba4B8TeO19 1067.44 monoclinic Cc a=11.512 b=6.667 c=19.700 β=105.734 Z=4 1455.3 4.872 double layers; SHG 1×KH2PO4 [3]
Ba2Mg2TeB2O10 632.52 orthorhombic Cmca a=6.177 b=10.383 c=12.956 Z=4 830.9 5 [7]
Na2Dy2TeO4(BO3)2 680.20 monoclinic P21/c a=6.3089, b=9.9808, c=6.7489; β=104.394°; Z=2 411.62 5.488 decompose 842.1 [1]
Na2Ho2TeO4(BO3)2 685.06 monoclinic P21/c a=6.3060, b=9.9360, c=6.7339; β=104.230°; Z=2 408.98 5.563 decompose 844.2 [1]
Na2Er2TeO4(BO3)2 689.72 monoclinic P21/c a=6.2964, b=9.9056, c=6.7089; β=104.110°; Z=2 405.81 5.645 decompose 850.5 [1]
Na2Tm2TeO4(BO3)2 693.06 monoclinic P21/c a=6.2801, b=9.8594, c=6.6918; β=104.010°; Z=2 401.89 5.727 decompose 852.0 [1]
Na2Yb2TeO4(BO3)2 701.28 monoclinic P21/c a=6.2631, b=9.8269, c=6.6741; β=103.972°; Z=2 398.62 5.843 decompose 871.0 [1]
Na2Lu2TeO4(BO3)2 705.14 monoclinic P21/c a=6.2588, b=9.7998, c=6.6539; β=103.714°; Z=2 396.48 5.907 decompose 878.5 [1]
Pb2Mg2TeB2O10 772.22 orthorhombic Cmca a=6.055 b=10.300 c=12.521 Z=4 780.9 7 [7]

References

Шаблон:Reflist

Шаблон:Borates