thorium borates are poorly described in the literature , with only a single crystallographically characterized example known , thb 2 o 5 . this paucity is surprising in light of the fact that a thorium borate was reported by j . j . berzelius in 1826 . in the course of attempting to understand crystallized portions of vitrified nuclear waste , a highly unusual thorium borate was discovered , [ thb 5 o 6 ( oh ) 6 ][ bo ( oh ) 2 ]. 2 . 5h 2 o ( hereinafter “ ndtb - 1 ”). the preparation of ndtb - 1 and related compounds according to formula 1 can be accomplished through the use of a boric acid reactive - flux , whereas previous investigations utilized either aqueous precipitation at room temperature or high temperature b 2 o 3 melts to prepare other thorium borate compounds . fig1 a illustrates an example of a view of a twelve - coordinate icosahedral geometry around th 4 + centers in ndtb - 1 . the structure of ndtb - 1 is a porous supertetrahedral 3d framework . the micro building blocks of this framework can be twelve - coordinate th 4 + surrounded by bo 3 and bo 4 anions . the bo 4 anions can chelate the thorium centers , and the bo 3 groups can occupy single vertices as shown in fig1 a . the structure of the bo 3 anions can be trigonal planar and the structure of the bo 4 anions can be tetrahedral . the ratio of the number of bo 3 / bo 4 anions can be 2 : 3 . the thorium atoms can reside on a site yielding an almost regular icosahedron with th — o bond distances of 2 . 566 ( 3 ) (× 6 ) and 2 . 575 ( 2 ) (× 6 ) å . this coordination number is known from classical anions such as [ th ( no 3 ) 6 ] 2 − , and is accomplished by combining the large size of the th 4 + cation ( 1 . 21 å ) with the small size and chelating nature of the borate anions . in another embodiment , the compound ndtb - 1 and other compounds according to formula 1 ( which includes other hydrates and non - hydrated compounds according to the formula ) may replace the thorium with cerium . as such , this disclosure is not meant to limit that which is disclosed herein to the particular thorium borate compound described above ( i . e . ndtb - 1 ), but can also be taken to include a cerium borate compound , where cerium replaces the presence of some or all of the thorium as well as other compounds according to formula 1 . accordingly , although much of the description herein refers specifically to ndtb - 1 , one skilled in the art will understand that the description is applicable to other compounds according to formula 1 . in some embodiments , the composition can comprise all thorium borate , all cerium borate , or a mixture of thorium and cerium borate compounds . fig1 b illustrates an example of b 10 o 24 ( 4 trigonal planar structures , 6 tetrahedral structures ) clusters with threefold symmetry that bridge between the th 4 + centers in ndtb - 1 . borate anions may be polymerized and can form the b 10 o 24 clusters with threefold symmetry that bridge between the thorium centers , and the hydroxide bridge between borate groups can be inferred from bond distances and bond - valence considerations . the bridging of the thorium centers by the borate clusters creates a supertetrahedral framework depicted in two formats in fig2 . one of the key features of ndtb - 1 and related compounds are the channels that extend along direction [ 110 ]. a view of the structure of this material is shown in fig3 a . x - ray diffraction studies reveal the presence of a highly disordered entity within the channels . thorium , or alternatively cerium atoms , and b 10 o 24 crown - like groups may not fill all of the space in the supertetrahedra , and as a result of this architecture , large free voids in the structure of ndtb - 1 are observed . the result of such combination is a regular 3d framework with a system of channels and cages . a general view of an example of an ndtb - 1 structure along the [ 110 ] direction is shown in fig3 a . the six channels can form a network that pierces the whole structure , and allows facile anionic and molecular transport for the exchange processes ( vide infra ). these channels intersect in the center of the supertetrahedra . the gates into the intersecting chamber have a hexagonal form and can be 9 . 4 × 7 . 4 å in size , as illustrated in fig3 b . in this embodiment , each cage can have four identical gates , and forms truncated tetrahedra . free void volume in ndtb - 1 is 43 %, which makes it the second most porous actinide compound currently known . the channel directions are at an angle of 30 ° to the gates , and in fig3 a an ellipse - like channel profile is observed . the preparation of this material from multiple sources as well as charge balance considerations can lead a person of skill in the art to suspect that disordered borate reside in the channels of ndtb - 1 . in fig4 a , solid - state 11 b mas nmr spectra show distinct signals from well - ordered bo 3 and bo 4 groups , as found from the single - crystal x - ray diffraction ( xrd ) data . as shown in fig4 b , the ordered bo 3 groups yield a characteristic mas powder pattern ( dashed ) with horns that correspond to the steep edge near + 15 ppm and the peak at + 7 . 5 ppm , best fit with an isotropic chemical shift δ = 17 . 5 ppm and quadrupolar coupling parameters cq = 2 . 65 mhz , η = 0 . however , a powder pattern for a well - ordered site cannot account for the broad area of intensity from 14 to 10 ppm , between the sharper bo 3 features . this intensity can be explained by the presence of a second bo 3 environment that experiences a distribution of electric field gradients , as shown in fig4 b , which can be calculated using a method described by d . coster , a . l . blumenfeld , j . j . fripiat , j . phys . chem . 1994 , 98 , 6201 - 6211 , the entirety of which is hereby incorporated by reference . a least - squares fit of the spectrum yielded for this disordered bo 3 an approximately gaussian distribution of cq values with a full - width of 0 . 9 mhz centered at an average of 2 . 0 mhz . although these values are not well - constrained in detail , a component profile of this general shape accounts for the difference between the observed spectrum and the lineshape expected for well - ordered bo 3 . this feature is in accord with the presence of a disordered bo 3 group as suspected from the crystal structure . in addition , the ratio of bo 3 to bo 4 integrated intensity , 0 . 82 ( 5 ), exceeds that expected from the 2 : 3 crystallographic ratio of the framework and provides further support for the existence of additional bo 3 groups in the channels . when the single crystal x - ray data and solid - state nmr spectroscopy are taken together , it can be concluded that ndtb - 1 is an exceedingly rare example of a cationic framework with extraframework borate anions residing in the symmetrical centers of the gates being used to maintain charge neutrality . anion exchange experiments can be conducted with a variety of common anions , beginning with halides . these studies , which combine inductively coupled plasma mass spectroscopy ( icp - ms ), energy dispersive spectroscopy ( eds ), and single crystal and powder x - ray diffraction , reveal that not only can anion exchange take place , but that the structure can remain intact throughout the exchange . more impressive is that fact that single crystals can retain their integrity throughout the exchange , although with these small anions , disorder in the channels remains a crystallographic problem . exchange experiments can be conducted with a variety of highly colored anions , such as but not limited to mno 4 − , cro 4 2 − , cr 2 o 7 2 − , reo 4 − , and aucl 4 − ( io 3 − and seo 3 2 − can also be studied ). the single crystals show the color of the transition metal anions within a few minutes . fig5 illustrates a uv - vis - nir spectrum absorption data using a micro - spectrophotometer that were collected from single crystals after exchange , and these clearly demonstrate the presence of the anions within the crystals . as illustrated in fig6 , the crystals can be cut , and the interior fluoresces a specific color according to the presence of the anions . the critical anion exchange experiments reveal the replacement of the extra framework borate anions with tco 4 − . owing to the intense nature of the charge transfer bands of tco 4 − ( pertechnetate ), relatively dilute solutions were used to follow its removal from solution using uv - vis spectroscopy . these studies from 10 mg of as - synthesized intact crystals of ndtb - 1 show rapid uptake of tco 4 − from solution with 72 % being removed in 36 hours , as shown in fig5 , providing a k d of 216 ml / g . fig7 a illustrates an example of a 99 tc mas - nmr spectrum of ndtb - 1 . 99 tc mas - nmr spectroscopy was used to probe the behavior of tco 4 − within the ndtb - 1 structure . although 99 tc is quadrupolar ( i = 9 / 2 ), the symmetry of the tco 4 − ion is sufficiently high that the quadrupolar broadening is limited and an aqueous tco 4 − ion exhibits an inherent peak width of approximately 3 hz in solution . the spectra in fig7 a show the presence of at least two sites where tco 4 − ions reside in the material . at 293 k , the two most conspicuous signals in the 99 tc mas nmr spectrum are a narrow peak near 0 ppm , with approximately 1 . 5 khz full - width at half - maximum , and a broader peak centered near − 40 ppm , with approximately 4 . 6 khz full - width at half - maximum . the intensity of the sharp , narrow peak diminishes markedly with decreasing temperature . this is consistent with its assignment to tco 4 − ions , which undergo rapid , near - isotropic tumbling near room temperature . the nmr spectra in fig7 a are also consistent with the interpretation that the chemical environment around the 99 tc nucleus is disturbed by the interaction with the cationic framework . as illustrated in fig7 a , the second conspicuous signal is a broader upfield signal centered near − 40 ppm , accompanied by sets of spinning sidebands denoted by asterisks . the signal can be modeled with a broadened second - order central - transition quadrupolar lineshape , but is not well - constrained . furthermore , the width and intensity of the spinning sidebands support an assignment to a dynamically rigid species , in contrast to a narrow downfield signal that suggests ion mobility . here , the broad signal exhibits complex nutation with an apparent π / 2 pulse width that is 2 - 3 times shorter than that for the narrow signal , suggesting that only the 99 tc nuclei represented by the broad signal experience a significant quadrupolar interaction . at 193 k , the smaller signal centered near 0 ppm contains about 6 ± 1 . 5 % of the total intensity . the reduction in intensity of this narrow signal with temperature indicates that all the 99 tc transitions are dynamically averaged into a narrow signal at room temperature . when the sample cools , the dynamic averaging diminishes , thus causing the signals , which correspond to the satellite transitions , to be broadened into the baseline , therefore only leaving the central transition . there is also evidence of a third signal on the broader peak at 293 k to 323 k near − 20 ppm that appears to resemble fine structure from second - order quadrupolar broadening . however , the narrow features appear to broaden with reduced temperature and have nearly the same chemical shift as the signal centered near − 40 ppm , thus suggesting instead the presence of a small amount of mobile tco 4 − ions in chemical environments . thus , results from fig7 a of 99 tc nmr experiments can show that both channels and the cages in ndtb - 1 are occupied by tco 4 − ions so that the net cationic charge of the framework is balanced . the narrow signal near 0 ppm can correspond to tco 4 − ions in the channels , which is consistent with the greater space for movement available for the ions . the broader upfield signal centered near − 40 ppm can be assigned to tco 4 − ions in the cavities . moreover , the 99 tc nmr data show that the tco 4 − ions in the cavities are significantly disordered . fig7 b illustrates an example of a 77 se mas - nmr spectrum of ndtb - 1 . here , ndtb - 1 samples were exchanged with seo 4 2 − ions to examine the selectivity of the cationic framework . in contrast to the 99 tc - mas nmr signals , the 77 se - mas nmr signal of the ndtb - 1 exchanged with seo 4 2 − ions produced only a single narrow signal , centered near 1045 ppm . the fact that the adsorption of seo 4 2 − ions gave only a single narrow signal suggests that the selectivity of ndtb - 1 is based upon the size - to - charge ratios of the tco 4 − and seo 4 2 − ions . the stronger coulombic interactions with the framework could lead to the exclusion of seo 4 2 − ions from the cages , though it is possible that the long t 1 values for 77 se that the seo 4 2 − ions in the cavities relaxed too slowly for detection . therefore , ndtb - 1 provides a cationic framework with the advantageous capacity to store the environmental contaminant tco 4 − ion as well as other complex anionic contaminants . ndtb - 1 was tested on nuclear waste solutions containing carbonate , sulfate , chloride , nitrate , and nitrite solutions in addition to tco 4 − ion . despite the presence of more than 300 - fold excesses of chloride and nitrate ions , and a 15 - fold excess of nitrite ions in a simulated low - activity melter recycle stream , ndtb - 1 selectively removed tco 4 − ions with a distribution coefficient k d of 16 . 2 - 22 . 9 ml / g from the solution . therefore , in accordance with preferred embodiments , ndtb - 1 and / or one or more compounds according to formula 1 ( and hydrates thereof ) may be blended , mixed , or otherwise combined or treated with target anions in solution , suspension or emulsion to result in the removal or sequestration of the anions . such methods find use in removal of the anionic contaminants from the environment , industrial wastestreams , and other sources . given the selectivity and degree of sequestration , such methods may find particularly beneficial use in the long - term storage of nuclear waste by providing for essentially non - leachable sequestration of pertechnetate and other harmful anions . ndtb - 1 and related compounds according to formula 1 represent a supertetrahedral cationic framework with advantageous anion exchange capabilities . it is a purely inorganic 3d cationic framework . also , the use of cerium , ce ( iv ), in substitution with thorium , could demonstrate additional utility outside of the nuclear industry . th ( no 3 ) 4 . 4h 2 o ( 0 . 2000 g ), boric acid ( 0 . 6717 g ), millipore - water ( 90 μl ) were loaded into a 23 ml autoclave . the autoclave was sealed and heated to 200 ° c . in a box furnace for 7 days . the autoclave was then cooled down to 160 ° c . at a rate of about 1 ° c ./ hour followed by cooling at a rate of 9 ° c ./ hour to room temperature . the product was washed with boiling water to remove excess boric acid , followed by rinsing with methanol . crystals in the form of octahedra and their fragments were isolated . crystals with improved morphology can be obtained by using th ( co 3 ) 2 as the source of thorium . single crystal x - ray diffraction and powder x - ray diffraction studies reveal that ndtb - 1 can be made as a pure phase with a yield of 72 . 8 % based on thorium . the process described above can also be accomplished with a cerium containing starting material . for example , a starting material such as ce 2 o ( no 3 ) 6 ( h 2 o ) 6 . 2h 2 o or ( nh 4 ) 2 ce ( no 3 ) 6 can be used to manufacture a cerium analog . x - ray structural analysis gathered the following data of [ thb 5 o 6 ( oh ) 6 ][ bo ( oh ) 2 ]. 2 . 5h 2 o ( ndtb - 1 ): colorless octahedron , crystal dimensions 0 . 131 × 0 . 132 × 0 . 134 mm , cubic , fd 3 ( no . 203 ), z = 16 , a = 17 . 4036 ( 16 ), v = 5271 . 3 ( 8 ) å 3 ( t = 100 k ), μ = 114 . 15 cm − 1 , r1 = 0 . 0194 , wr2 = 0 . 0519 . a bruker apexii quazar diffractometer was configured with the following parameters : θ max = 57 . 78 °, mo kα , λ = 0 . 71073 å , 0 . 5 ° ω scans , 15189 reflections measured , 579 independent reflections all of which were included in the refinement . the data was corrected for lorentz - polarization effects and for absorption , structure was solved by direct methods , anisotropic refinement of f2 by full - matrix least - squares , 48 parameters . the program for crystal structure determination from single - crystal diffraction data can be described by g . m . sheldrick , shelxtl pc , version 5 . 0 , siemens analytical x - ray instruments , inc . ; madison , wis . 1994 , the entirety of which is hereby incorporated by reference . further details of the crystal structure investigation may be obtained from the fachinformationzentrum karlsruhe , d - 76344 eggenstein - leopoldshafen , germany ( crysdata @ fiz - karlsruhe . de ) on quoting numbers csd 421217 . while the components and techniques of the invention have been described with a certain degree of particularity , it is manifest that many changes may be made in the specific designs , constructions and methodology herein above described without departing from the spirit and scope of this disclosure . it should be understood that the invention is not limited to the embodiments set forth herein for purposes of exemplification , but is to be defined only by a fair reading of the appended claims , including the full range of equivalency to which each element thereof is entitled .