|
Topaz |
|
Wunder B, Rubie D C, Ross C R, Medenbach O, Seifert F, Schreyer W |
|
American Mineralogist 78 (1993) 285-297 |
|
Synthesis, stability, and properties of Al2SiO4(OH)2: A fully hydrated |
|
analogue of topaz |
|
_database_code_amcsd 0001552 |
|
4.7238 8.9473 8.3900 90 90 90 Pbnm |
|
atom x y z U(1,1) U(2,2) U(3,3) U(1,2) U(1,3) U(2,3) |
|
Al -.0948 .1322 .0798 .0098 .0089 .0137 .0002 .0002 .0000 |
|
Si .4019 -.0595 .25 .0090 .0088 .0145 .0000 0 0 |
|
O1 -.2897 .0261 .25 .0088 .0095 .0150 -.0006 0 0 |
|
O2 .0554 .2558 .25 .0108 .0102 .0150 -.0003 0 0 |
|
O3 .2142 -.0069 .0940 .0101 .0100 .0136 .0010 .0006 .0000 |
|
OH -.4103 .2508 .0665 .0106 .0122 .0167 .0021 .0001 .0016 |
|
|
| Download AMC data (View Text File) Download CIF data (View Text File) Download diffraction data (View Text File) View JMOL 3-D Structure (permalink) |
  |
|
Topaz |
|
Northrup P A, Leinenweber K, Parise J B |
|
American Mineralogist 79 (1994) 401-404 |
|
The location of H in the high-pressure synthetic Al2SiO4(OH)2 topaz analogue |
|
Sample fluor-topaz from a Mexican rhyolite |
|
_database_code_amcsd 0001642 |
|
4.652 8.801 8.404 90 90 90 Pbnm |
|
atom x y z Biso |
|
Al .90303 .13090 .08283 .34 |
|
Si .39723 .94035 .25 .29 |
|
O1 .7036 .0321 .25 .38 |
|
O2 .4577 .7560 .25 .39 |
|
O3 .2102 .9892 .0924 .37 |
|
F .5982 .2525 .0561 .52 |
|
|
| Download AMC data (View Text File) Download CIF data (View Text File) Download diffraction data (View Text File) View JMOL 3-D Structure (permalink) |
  |
|
Topaz |
|
Northrup P A, Leinenweber K, Parise J B |
|
American Mineralogist 79 (1994) 401-404 |
|
The location of H in the high-pressure synthetic Al2SiO4(OH)2 topaz analogue |
|
Sample OH synthetic |
|
_database_code_amcsd 0001643 |
|
4.7203 8.9207 8.4189 90 90 90 Pbnm |
|
atom x y z occ Biso |
|
Al .90499 .13210 .07984 .33 |
|
Si .40189 .94045 .25 .29 |
|
O1 .7104 .0262 .25 .38 |
|
O2 .4439 .7561 .25 .36 |
|
O3 .2141 .9929 .0943 .38 |
|
Oh .5906 .2507 .0659 .52 |
|
H1 .443 .199 .088 .5 2.7 |
|
H2 .607 .281 .151 .5 7.1 |
|
|
| Download AMC data (View Text File) Download CIF data (View Text File) Download diffraction data (View Text File) View JMOL 3-D Structure (permalink) |
  |
|
Topaz |
|
Diego Gatta G, Nestola F, Bromiley G D, Loose A |
|
American Mineralogist 91 (2006) 1839-1846 |
|
New insight into crystal chemistry of topaz: a multi-methodological study |
|
Locality: Ouro Preto, Minas Gerias, Brazil |
|
Sample: X-ray refinement at T = 298 K |
|
Note: x(F4) corrected |
|
_database_code_amcsd 0004243 |
|
4.6601 8.8260 8.3778 90 90 90 Pbnm |
|
atom x y z occ Uiso U(1,1) U(2,2) U(3,3) U(1,2) U(1,3) U(2,3) |
|
Al .9053 .13131 .0816 .0039 .0034 .0040 .00436 .00008 -.00010 .00008 |
|
Si .39976 .94088 .25 .0033 .0027 .0036 .0038 .0001 0 0 |
|
O1 .7064 .0311 .25 .005 .0041 .0054 .0054 .0017 0 0 |
|
O2 .4516 .7564 .25 .0049 .0059 .0037 .0050 .0009 0 0 |
|
O3 .2114 .98979 .09284 .0047 .0046 .0047 .0047 .0007 -.0011 -.0003 |
|
F4 .5982 .25263 .05988 .0083 .0075 .0084 .0089 -.0023 .0005 .0013 |
|
|
| Download AMC data (View Text File) Download CIF data (View Text File) Download diffraction data (View Text File) View JMOL 3-D Structure (permalink) |
  |
|
Topaz |
|
Diego Gatta G, Nestola F, Bromiley G D, Loose A |
|
American Mineralogist 91 (2006) 1839-1846 |
|
New insight into crystal chemistry of topaz: a multi-methodological study |
|
Locality: Ouro Preto, Minas Gerias, Brazil |
|
Sample: Neutron refinement at T = 298 K |
|
_database_code_amcsd 0004244 |
|
4.667 8.834 8.395 90 90 90 Pbnm |
|
atom x y z occ Uiso U(1,1) U(2,2) U(3,3) U(1,2) U(1,3) U(2,3) |
|
Al .9051 .13123 .0817 .0037 .0037 .0026 .0048 .0002 -.00001 .0002 |
|
Si .3996 .94088 .25 .0030 .0026 .0020 .0045 .0003 0 0 |
|
O1 .7059 .03129 .25 .0045 .0038 .0041 .0054 -.0011 0 0 |
|
O2 .4529 .75627 .25 .0046 .0055 .0026 .0057 .0008 0 0 |
|
O3 .2114 .98961 .09270 .0045 .0043 .0037 .0054 .0008 -.0011 -.0002 |
|
F4 .5976 .25265 .05971 .78 .0067 .0060 .0056 .0084 .0022 -.0008 .0010 |
|
O4 .5976 .25265 .05971 .22 .0067 .0060 .0056 .0084 .0022 -.0008 .0010 |
|
H4 .495 .252 .1629 .22 .037 .041 .049 .019 .026 .015 .014 |
|
|
| Download AMC data (View Text File) Download CIF data (View Text File) Download diffraction data (View Text File) View JMOL 3-D Structure (permalink) |
  |
|
Topaz |
|
Diego Gatta G, Nestola F, Bromiley G D, Loose A |
|
American Mineralogist 91 (2006) 1839-1846 |
|
New insight into crystal chemistry of topaz: a multi-methodological study |
|
Locality: Ouro Preto, Minas Gerias, Brazil |
|
Sample: Neutron refinement at T = 10 K |
|
_database_code_amcsd 0004245 |
|
4.657 8.838 8.426 90 90 90 Pbnm |
|
atom x y z occ Uiso U(1,1) U(2,2) U(3,3) U(1,2) U(1,3) U(2,3) |
|
Al .9056 .1313 .0817 .0029 .0028 .0013 .00472 .0003 -.0005 .0006 |
|
Si .3996 .9409 .25 .0027 .0018 .0011 .0052 .0003 0 0 |
|
O1 .7069 .0312 .25 .0038 .0039 .0026 .0050 -.0004 0 0 |
|
O2 .4528 .7562 .25 .0039 .0042 .0014 .0062 .0012 0 0 |
|
O3 .2117 .9899 .0926 .0037 .0031 .0020 .0061 .0006 -.0006 .0001 |
|
F4 .5973 .2525 .05992 .79 .0047 .0040 .0028 .0072 .0008 -.0003 -.0001 |
|
O4 .5973 .2525 .05992 .21 .0047 .0040 .0028 .0072 .0008 -.0003 -.0001 |
|
H4 .492 .251 .1637 .21 .025 .027 .027 .022 .010 .015 .008 |
|
|
| Download AMC data (View Text File) Download CIF data (View Text File) Download diffraction data (View Text File) View JMOL 3-D Structure (permalink) |
  |
|
Topaz |
|
Komatsu K, Kagi H, Marshall W G, Kuribayashi T, Parise J B, Kudoh Y |
|
American Mineralogist 93 (2008) 217-227 |
|
Pressure dependence of the hydrogen-bond geometry in topaz-OD from neutron |
|
powder diffraction |
|
Locality: synthetic |
|
Sample: P = 0.0001 GPa |
|
_database_code_amcsd 0004516 |
|
4.7279 8.9269 8.4214 90 90 90 Pbnm |
|
atom x y z occ Uiso |
|
Al .9062 .13273 .0797 .0053 |
|
Si .4020 .94072 .25 .00155 |
|
O1 .7098 .02717 .25 .00350 |
|
O2 .4446 .75694 .25 .00350 |
|
O3 .21408 .99286 .09325 .00350 |
|
O4 .58996 .25057 .06533 .00359 |
|
D1 .4403 .1937 .1222 .432 .0744 |
|
D2 .556 .2978 .1720 .296 .0653 |
|
H1 .4403 .1937 .1222 .141 .0744 |
|
H2 .556 .2978 .1720 .131 .0653 |
|
|
| Download AMC data (View Text File) Download CIF data (View Text File) Download diffraction data (View Text File) View JMOL 3-D Structure (permalink) |
  |
|
Topaz |
|
Komatsu K, Kagi H, Marshall W G, Kuribayashi T, Parise J B, Kudoh Y |
|
American Mineralogist 93 (2008) 217-227 |
|
Pressure dependence of the hydrogen-bond geometry in topaz-OD from neutron |
|
powder diffraction |
|
Locality: synthetic |
|
Sample: 7 tons, P = 0.0001 GPa |
|
_database_code_amcsd 0004517 |
|
4.7316 8.9328 8.4286 90 90 90 Pbnm |
|
atom x y z occ Uiso |
|
Al .9060 .1310 .0813 .0016 |
|
Si .4034 .9432 .25 .0028 |
|
O1 .7154 .0264 .25 .0049 |
|
O2 .4450 .7572 .25 .0049 |
|
O3 .2148 .9950 .0931 .0049 |
|
O4 .5932 .2529 .0640 .0049 |
|
D1 .445 .1889 .1161 .59 .081 |
|
D2 .545 .2954 .1714 .41 .045 |
|
|
| Download AMC data (View Text File) Download CIF data (View Text File) Download diffraction data (View Text File) View JMOL 3-D Structure (permalink) |
  |
|
Topaz |
|
Komatsu K, Kagi H, Marshall W G, Kuribayashi T, Parise J B, Kudoh Y |
|
American Mineralogist 93 (2008) 217-227 |
|
Pressure dependence of the hydrogen-bond geometry in topaz-OD from neutron |
|
powder diffraction |
|
Locality: synthetic |
|
Sample: 15 tons, P = 0.7 GPa |
|
_database_code_amcsd 0004518 |
|
4.7248 8.9250 8.4100 90 90 90 Pbnm |
|
atom x y z occ Uiso |
|
Al .904 .1347 .0830 .0111 |
|
Si .4006 .9401 .25 .0111 |
|
O1 .7102 .0288 .25 .0046 |
|
O2 .4440 .7580 .25 .0046 |
|
O3 .2128 .9927 .0918 .0046 |
|
O4 .5948 .2506 .0637 .0046 |
|
D1 .457 .1870 .1211 .59 .060 |
|
D2 .520 .283 .1687 .41 .047 |
|
|
| Download AMC data (View Text File) Download CIF data (View Text File) Download diffraction data (View Text File) View JMOL 3-D Structure (permalink) |
  |
|
Topaz |
|
Komatsu K, Kagi H, Marshall W G, Kuribayashi T, Parise J B, Kudoh Y |
|
American Mineralogist 93 (2008) 217-227 |
|
Pressure dependence of the hydrogen-bond geometry in topaz-OD from neutron |
|
powder diffraction |
|
Locality: synthetic |
|
Sample: 25 tons, P = 1.9 GPa |
|
_database_code_amcsd 0004519 |
|
4.7129 8.9046 8.3802 90 90 90 Pbnm |
|
atom x y z occ Uiso |
|
Al .902 .1340 .0843 .0076 |
|
Si .4035 .9417 .25 .0076 |
|
O1 .7136 .0288 .25 .0060 |
|
O2 .443 .7580 .25 .0060 |
|
O3 .2150 .9927 .0920 .0060 |
|
O4 .5930 .2533 .0662 .0060 |
|
D1 .457 .1879 .1209 .59 .061 |
|
D2 .526 .285 .1718 .41 .041 |
|
|
| Download AMC data (View Text File) Download CIF data (View Text File) Download diffraction data (View Text File) View JMOL 3-D Structure (permalink) |
  |
|
Topaz |
|
Komatsu K, Kagi H, Marshall W G, Kuribayashi T, Parise J B, Kudoh Y |
|
American Mineralogist 93 (2008) 217-227 |
|
Pressure dependence of the hydrogen-bond geometry in topaz-OD from neutron |
|
powder diffraction |
|
Locality: synthetic |
|
Sample: 38 tons, P = 3.6 GPa |
|
_database_code_amcsd 0004520 |
|
4.6978 8.8786 8.3390 90 90 90 Pbnm |
|
atom x y z occ Uiso |
|
Al .904 .1341 .090 .0078 |
|
Si .3978 .9412 .25 .0078 |
|
O1 .7107 .0279 .25 .0062 |
|
O2 .442 .7573 .25 .0062 |
|
O3 .2151 .9930 .0896 .0062 |
|
O4 .5945 .2540 .0676 .0062 |
|
D1 .464 .1846 .1215 .59 .053 |
|
D2 .526 .278 .1756 .41 .042 |
|
|
| Download AMC data (View Text File) Download CIF data (View Text File) Download diffraction data (View Text File) View JMOL 3-D Structure (permalink) |
  |
|
Topaz |
|
Komatsu K, Kagi H, Marshall W G, Kuribayashi T, Parise J B, Kudoh Y |
|
American Mineralogist 93 (2008) 217-227 |
|
Pressure dependence of the hydrogen-bond geometry in topaz-OD from neutron |
|
powder diffraction |
|
Locality: synthetic |
|
Sample: 46 tons, P = 4.7 GPa |
|
_database_code_amcsd 0004521 |
|
4.6888 8.8624 8.3147 90 90 90 Pbnm |
|
atom x y z occ Uiso |
|
Al .904 .1338 .090 .0105 |
|
Si .402 .9418 .25 .0105 |
|
O1 .712 .0282 .25 .0067 |
|
O2 .445 .7584 .25 .0067 |
|
O3 .2175 .9946 .0907 .0067 |
|
O4 .5922 .2546 .0705 .0067 |
|
D1 .462 .1822 .119 .59 .064 |
|
D2 .516 .274 .1772 .41 .048 |
|
|
| Download AMC data (View Text File) Download CIF data (View Text File) Download diffraction data (View Text File) View JMOL 3-D Structure (permalink) |
  |
|
Topaz |
|
Komatsu K, Kagi H, Marshall W G, Kuribayashi T, Parise J B, Kudoh Y |
|
American Mineralogist 93 (2008) 217-227 |
|
Pressure dependence of the hydrogen-bond geometry in topaz-OD from neutron |
|
powder diffraction |
|
Locality: synthetic |
|
Sample: 58 tons, P = 6.2 GPa |
|
_database_code_amcsd 0004522 |
|
4.6755 8.8410 8.2823 90 90 90 Pbnm |
|
atom x y z occ Uiso |
|
Al .901 .1325 .090 .0090 |
|
Si .405 .9397 .25 .0090 |
|
O1 .718 .0251 .25 .0095 |
|
O2 .443 .7549 .25 .0095 |
|
O3 .2140 .9932 .0933 .0095 |
|
O4 .593 .2543 .0708 .0095 |
|
D1 .467 .180 .124 .59 .066 |
|
D2 .510 .272 .178 .41 .046 |
|
|
| Download AMC data (View Text File) Download CIF data (View Text File) Download diffraction data (View Text File) View JMOL 3-D Structure (permalink) |
  |
|
Topaz |
|
Komatsu K, Kagi H, Marshall W G, Kuribayashi T, Parise J B, Kudoh Y |
|
American Mineralogist 93 (2008) 217-227 |
|
Pressure dependence of the hydrogen-bond geometry in topaz-OD from neutron |
|
powder diffraction |
|
Locality: synthetic |
|
Sample: 70 tons, P = 7.5 GPa |
|
_database_code_amcsd 0004523 |
|
4.6658 8.8210 8.2573 90 90 90 Pbnm |
|
atom x y z occ Uiso |
|
Al .906 .1316 .088 .0133 |
|
Si .404 .9415 .25 .0133 |
|
O1 .718 .0268 .25 .0101 |
|
O2 .443 .7570 .25 .0101 |
|
O3 .2193 .9967 .0913 .0101 |
|
O4 .5934 .2538 .0710 .0101 |
|
D1 .456 .1808 .117 .59 .078 |
|
D2 .519 .274 .1800 .41 .037 |
|
|
| Download AMC data (View Text File) Download CIF data (View Text File) Download diffraction data (View Text File) View JMOL 3-D Structure (permalink) |
  |
|
Topaz-OH |
|
Kanzaki M |
|
American Mineralogist 95 (2010) 1349-1352 |
|
Crystal structure of a new high-pressure polymorph of topaz-OH |
|
Locality: synthetic |
|
P = 14 GPa, T = 1400 C |
|
_database_code_amcsd 0017560 |
|
4.72318 8.91480 2.77276 90 90 90 Pbnm |
|
atom x y z occ Uiso |
|
AlT .5876 .4402 .25 .01 .0163 |
|
SiT .5876 .4402 .25 .20 .0163 |
|
AlOc1 .5812 .8587 .25 .60 .0213 |
|
SiOc1 .5812 .8587 .25 .11 .0213 |
|
AlOc2 .579 .6298 .25 .07 .0163 |
|
SiOc2 .579 .6298 .25 .01 .0163 |
|
O1 .5891 .2482 .25 .66 .0282 |
|
OH1 .5891 .2482 .25 .34 .0282 |
|
O2 .2365 .5098 .25 .66 .0334 |
|
OH2 .2365 .5098 .25 .34 .0334 |
|
|
| Download AMC data (View Text File) Download CIF data (View Text File) Download diffraction data (View Text File) View JMOL 3-D Structure (permalink) |
  |
|
Topaz |
|
Alberico A, Ferrando S, Ivaldi G, Ferraris G |
|
European Journal of Mineralogy 15 (2003) 875-881 |
|
X-ray single-crystal structure refinement of an OH-rich topaz from Sulu UHP terrane |
|
(Eastern China) - Structural foundation of the correlation between cell parameters |
|
and fluorine content |
|
Locality: Sulu UHP terrane, Eastern China |
|
_database_code_amcsd 0007017 |
|
4.6696 8.8486 8.3915 90 90 90 Pbnm |
|
atom x y z occ Uiso U(1,1) U(2,2) U(3,3) U(1,2) U(1,3) U(2,3) |
|
Al .90543 .13126 .08148 .00543 .00555 .00531 .00544 .00012 -.00009 -.00012 |
|
Si .40000 .94092 1/4 .00471 .00465 .00482 .00467 .00017 0 0 |
|
O1 .79373 .53096 1/4 .00619 .00546 .00702 .00610 .00087 0 0 |
|
O2 .45186 .75634 1/4 .00619 .00705 .00482 .00668 .00063 0 0 |
|
O3 .78824 .01025 .90720 .00607 .00588 .00641 .00590 .00101 -.00124 .00010 |
|
F .90221 .75257 .05998 .70 .00823 .00779 .00843 .00846 -.00190 .00054 .00087 |
|
O .90221 .75257 .05998 .30 .00823 .00779 .00843 .00846 -.00190 .00054 .00087 |
|
H .96 .76 .15 .30 |
|
|
| Download AMC data (View Text File) Download CIF data (View Text File) Download diffraction data (View Text File) View JMOL 3-D Structure (permalink) |
  |
|
Topaz |
|
Gatta G D, Nestola F, Ballaran T B |
|
Physics and Chemistry of Minerals 33 (2006) 235-242 |
|
Elastic behaviour and structural evolution |
|
of topaz at high pressure |
|
Locality: Ouro Preto, Minas Gerias, Brazil |
|
Sample: P = .0001 GPa |
|
_database_code_amcsd 0009026 |
|
4.6627 8.8343 8.3867 90 90 90 Pbnm |
|
atom x y z Uiso |
|
Al .9047 .1309 .0817 .0053 |
|
Si .4005 .9409 .25 .0044 |
|
O1 .7963 .5321 .25 .0057 |
|
O2 .4531 .7559 .25 .0035 |
|
O3 .7904 .0108 .9069 .0064 |
|
FO .9006 .7533 .0599 .0117 |
|
|
| Download AMC data (View Text File) Download CIF data (View Text File) Download diffraction data (View Text File) View JMOL 3-D Structure (permalink) |
  |
|
Topaz |
|
Gatta G D, Nestola F, Ballaran T B |
|
Physics and Chemistry of Minerals 33 (2006) 235-242 |
|
Elastic behaviour and structural evolution |
|
of topaz at high pressure |
|
Locality: Ouro Preto, Minas Gerias, Brazil |
|
Sample: P = 3.14 GPa |
|
_database_code_amcsd 0009027 |
|
4.6325 8.7938 8.3254 90 90 90 Pbnm |
|
atom x y z Uiso |
|
Al .9047 .1307 .0816 .0053 |
|
Si .4009 .9407 .25 .0041 |
|
O1 .7919 .5295 .25 .0044 |
|
O2 .4471 .7547 .25 .0057 |
|
O3 .7876 .0101 .9080 .0053 |
|
FO .9021 .7529 .0625 .0129 |
|
|
| Download AMC data (View Text File) Download CIF data (View Text File) Download diffraction data (View Text File) View JMOL 3-D Structure (permalink) |
  |
|
Topaz |
|
Gatta G D, Nestola F, Ballaran T B |
|
Physics and Chemistry of Minerals 33 (2006) 235-242 |
|
Elastic behaviour and structural evolution |
|
of topaz at high pressure |
|
Locality: Ouro Preto, Minas Gerias, Brazil |
|
Sample: P = 5.79 GPa |
|
_database_code_amcsd 0009028 |
|
4.6071 8.7614 8.2765 90 90 90 Pbnm |
|
atom x y z Uiso |
|
Al .9064 .1309 .0811 .0055 |
|
Si .4023 .9404 .25 .0047 |
|
O1 .7884 .5295 .25 .0046 |
|
O2 .4482 .7555 .25 .0047 |
|
O3 .7856 .0094 .9092 .0059 |
|
FO .9046 .7531 .0637 .0110 |
|
|
| Download AMC data (View Text File) Download CIF data (View Text File) Download diffraction data (View Text File) View JMOL 3-D Structure (permalink) |
  |
|
Topaz |
|
Gatta G D, Nestola F, Ballaran T B |
|
Physics and Chemistry of Minerals 33 (2006) 235-242 |
|
Elastic behaviour and structural evolution |
|
of topaz at high pressure |
|
Locality: Ouro Preto, Minas Gerias, Brazil |
|
Sample: P = 8.39 GPa |
|
_database_code_amcsd 0009029 |
|
4.5841 8.7308 8.2316 90 90 90 Pbnm |
|
atom x y z Uiso |
|
Al .9069 .1313 .0807 .0041 |
|
Si .4016 .9413 .25 .0041 |
|
O1 .7882 .5276 .25 .0037 |
|
O2 .4490 .7546 .25 .0037 |
|
O3 .7845 .0086 .9094 .0037 |
|
FO .9075 .7531 .0653 .0112 |
|
|
| Download AMC data (View Text File) Download CIF data (View Text File) Download diffraction data (View Text File) View JMOL 3-D Structure (permalink) |
  |
|
Topaz |
|
Chen J, Lager G A, Kunz M, Hansen T C, Ulmer P |
|
Acta Crystallographica E61 (2005) i253-i255 |
|
A Rietveld refinement using neutron powder diffraction data of a |
|
fully deuterated topaz, Al2SiO4(OD)2 |
|
Locality: synthetic |
|
_database_code_amcsd 0010464 |
|
4.72820 8.9320 8.4309 90 90 90 Pbnm |
|
atom x y z occ Uiso |
|
Al .9071 .1325 .0779 .0030 |
|
Si .4032 .9404 .25 .0002 |
|
O1 .7080 .0260 .25 .0015 |
|
O2 .4431 .7551 .25 .0017 |
|
O3 .2129 .9922 .0946 .0031 |
|
O4 .5917 .2504 .0661 .0048 |
|
D1 .4400 .1858 .1031 .5 .0450 |
|
D2 .5320 .2811 .1675 .5 .0480 |
|
|
| Download AMC data (View Text File) Download CIF data (View Text File) Download diffraction data (View Text File) View JMOL 3-D Structure (permalink) |
  |
Multiple datasets can be concatenated into a single downloadable file by selecting the datasets and then clicking
Multiple datasets can be downloaded as individual files inside a ZIP archive by selecting the datasets and then clicking
Total number of retrieved datasets: