This component is mentioned in an article called "Novel geopolymer materials containing borate and phosphate structural units". I've never heard about this before, and a google search didn't really give an answer it seems.

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    $\begingroup$ google for it. If you have a problem with guessing structure of a compounds, but have a name, google usually helps. Sometimes you need enclose it in quotes. $\endgroup$ – permeakra Sep 21 '16 at 10:54
  • $\begingroup$ Also try googling the words individually. If you did that for pyroborate, you would find definitions that would solve the problem for you. $\endgroup$ – Curt F. Sep 21 '16 at 12:08

Lithium pyroborate ($\ce{Li2B4O7}$) is the salt of lithium ($\ce{Li}$) and pyroboric acid ($\ce{H2B4O7}$).


The prefix ortho- designates an acid with the maximum number of hydroxyl ($\ce{OH}$) groups [reference]. For boron ($\ce{B}$), orthoboric acid is $\ce{H3BO3}$ (also written as $\ce{B(OH)3}$ to show that there are $3$ hydroxyl groups).

The prefix pyro- here seems to not match with the usual usage, so I will not be explaining the usual usage here. One common feature between this and the usual usage is that their molecular formulas are multiples of the ortho acid's molecular formulas, minus some water molecules:

$$\ce{4H3BO3 -> H2B4O7 + 5H2O}$$


Some proposed structures of lithium pyroborate:

Some proposed structures of pyroboric acid:

The above are modified from two proposed structures of sodium pyroborate, with the first one referenced here and the second one referenced here.

  • $\begingroup$ Why the downvote??? $\endgroup$ – Nilay Ghosh Sep 21 '16 at 12:43
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    $\begingroup$ Because, obviously, the structure is completely wrong? $\endgroup$ – permeakra Sep 21 '16 at 12:48
  • $\begingroup$ @permeakra There are at least 4 structures of tetraborate that I found online. $\endgroup$ – DHMO Sep 21 '16 at 12:53
  • $\begingroup$ @user34388 - The formula doesn't include hydrogen, so your proposed structures that do include hydrogen are incorrect. The first image you have is correct. See ChemSpider. $\endgroup$ – Todd Minehardt Sep 21 '16 at 13:18
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    $\begingroup$ @ToddMinehardt My proposed structures that do include hydrogen are pyroboic acid structures. $\endgroup$ – DHMO Sep 21 '16 at 13:19

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