Buy article online - an online subscription or single-article purchase is required to access this article.
Download citation
Download citation
link to html
The crystal structure of silicalite (SiO2) with a substantial amount of structural hydroxyl groups [Si(1−x)O(2−4x)(OH)4x, with 0.08 < x < 0.10] has been refined from neutron powder diffraction data measured using the HRPD instrument at the ISIS pulsed neutron source. Powder data were collected on the as-synthesized orthorhombic sample at 298 K, and on the deuterated monoclinic sample at 100 K. Preferential location of Si-atom vacancies was found on four out of 12 independent T sites in the orthorhombic silicalite [Si(6), Si(7), Si(10) and Si(11)], although the H atoms of the substituting hydroxyl groups could not be located because of the low statistical site occupancy on multiple sites. No significant population of D atoms or of Si vacancies was found in the tetrahedral sites of the monoclinic sample. The detected long-range order of adjacent Si atoms in defective orthorhombic [MFI] structures is compatible with a mechanism of Si vacancy clustering and with the model of hydroxyl nests assumed in the literature on the basis of IR spectroscopic evidence. Crystal data: orthorhombic, Pnma, Z = 8, a = 20.0511 (1), b = 19.8757 (1), c = 13.36823 (9) Å, V = 5327.62 (5) Å3, Dx = 1.798 g cm−3, Mr = 721.01; monoclinic, P21/n, Z = 4, a = 19.8352 (2), b = 20.0903 (2), c = 13.3588 (1) Å, β = 90.892 (1)°, V = 5322.78 (6) Å3, Dx = 1.799 g cm−3, Mr = 1442.02.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108768199008927/na0094sup1.cif
Contains datablocks global, I, II

txt

Text file https://doi.org/10.1107/S0108768199008927/na0094Isup2.txt
Supplementary material

txt

Text file https://doi.org/10.1107/S0108768199008927/na0094IIsup3.txt
Supplementary material

txt

Text file https://doi.org/10.1107/S0108768199008927/na0094sup4.txt
Supplementary material

Computing details top

(I) top
Crystal data top
H3.6O24Si11.04c = 13.36823 (9) Å
Mr = 721.01V = 5327.62 (5) Å3
Orthorhombic, PnmaZ = 8
Hall symbol: -P 2ac 2nDx = 1.798 Mg m3
a = 20.0511 (1) ÅNeutron radiation, λ = 1.22 Å
b = 19.8757 (1) Å
Data collection top
h = l =
k =
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Si(1)0.4245 (3)0.0601 (3)0.3315 (4)0.0256 (4)
Si(2)0.3083 (3)0.0281 (2)0.1860 (4)0.0256 (4)
Si(3)0.2779 (3)0.0612 (3)0.0341 (4)0.0256 (4)
Si(4)0.1182 (3)0.0628 (3)0.0283 (4)0.0256 (4)
Si(5)0.0749 (3)0.0289 (3)0.1874 (5)0.0256 (4)
Si(6)0.1888 (3)0.0607 (3)0.3272 (4)0.0256 (4)
Si(7)0.4249 (3)0.1723 (2)0.3265 (4)0.0256 (4)
Si(8)0.3087 (3)0.1321 (3)0.1842 (4)0.0256 (4)
Si(9)0.2721 (3)0.1754 (2)0.0335 (4)0.0256 (4)
Si(10)0.1199 (3)0.1738 (2)0.0320 (4)0.0256 (4)
Si(11)0.0723 (3)0.1292 (3)0.1809 (5)0.0256 (4)
Si(12)0.1858 (3)0.1732 (2)0.3233 (4)0.0256 (4)
O(1)0.3777 (3)0.0495 (5)0.2359 (5)0.0408 (4)
O(2)0.3060 (5)0.0631 (4)0.0782 (4)0.0408 (4)
O(3)0.1981 (3)0.0601 (4)0.0274 (4)0.0408 (4)
O(4)0.0989 (3)0.0663 (4)0.0876 (4)0.0408 (4)
O(5)0.1161 (3)0.0616 (5)0.2776 (5)0.0408 (4)
O(6)0.2487 (3)0.0618 (5)0.2482 (5)0.0408 (4)
O(7)0.3745 (4)0.1628 (4)0.2343 (6)0.0408 (4)
O(8)0.3077 (5)0.1545 (3)0.0694 (4)0.0408 (4)
O(9)0.1963 (3)0.1505 (3)0.0227 (5)0.0408 (4)
O(10)0.0876 (4)0.1665 (4)0.0772 (5)0.0408 (4)
O(11)0.1152 (3)0.1546 (4)0.2746 (6)0.0408 (4)
O(12)0.2437 (4)0.1531 (4)0.2462 (6)0.0408 (4)
O(13)0.3153 (4)0.0521 (2)0.1876 (4)0.0408 (4)
O(14)0.0840 (3)0.0501 (3)0.1678 (5)0.0408 (4)
O(15)0.4193 (4)0.1321 (4)0.3842 (6)0.0408 (4)
O(16)0.4054 (4)0.0006 (4)0.4069 (6)0.0408 (4)
O(17)0.4014 (4)0.1346 (4)0.4264 (6)0.0408 (4)
O(18)0.1906 (5)0.1319 (3)0.3828 (5)0.0408 (4)
O(19)0.1899 (5)0.0019 (3)0.4089 (5)0.0408 (4)
O(20)0.1959 (6)0.1323 (3)0.4251 (4)0.0408 (4)
O(21)0.0021 (3)0.0441 (4)0.2093 (5)0.0408 (4)
O(22)0.0019 (3)0.1513 (5)0.2103 (6)0.0408 (4)
O(23)0.4287 (7)0.250.3573 (9)0.0408 (4)
O(24)0.2025 (6)0.250.3473 (8)0.0408 (4)
O(25)0.2881 (6)0.250.0722 (7)0.0408 (4)
O(26)0.1136 (7)0.250.0696 (9)0.0408 (4)
Bond lengths (Å) top
Si(1)—O(1/15/16)1.600 (2)Si(7)—O(7/17/23)1.602 (2)
Si(2)—O(1/2/6)1.601 (2)Si(8)—O(8/12/13)1.599 (2)
Si(3)—O(2/3)1.603 (2)Si(9)—O(8/9/25)1.603 (2)
Si(4)—O(3/4)1.600 (2)Si(10)—O(9/10/26)1.602 (2)
Si(5)—O(5/14/21)1.601 (2)Si(11)—O(10/11/14/22)1.601 (2)
Si(6)—O(5/6/18/19)1.600 (2)Si(12)—O(11/12/20/24)1.600 (2)
(II) top
Crystal data top
H3.6O24Si11.04c = 13.3588 (1) Å
Mr = 1442.02β = 90.892 (1)°
Monoclinic, P21/nV = 5322.78 (6) Å3
Hall symbol: -P 2ynZ = 4
a = 19.8352 (2) ÅDx = 1.799 Mg m3
b = 20.0903 (2) ÅNeutron radiation, λ = 1.22 Å
Data collection top
h = l =
k =
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Si(1)0.0622 (4)0.4223 (4)0.3282 (6)0.0114 (5)
Si(2)0.0329 (4)0.3195 (4)0.1641 (5)0.0114 (5)
Si(3)0.0605 (4)0.2820 (4)0.0600 (5)0.0114 (5)
Si(4)0.0628 (4)0.1253 (4)0.0358 (7)0.0114 (5)
Si(5)0.0307 (4)0.0781 (4)0.1760 (6)0.0114 (5)
Si(6)0.0546 (4)0.2006 (4)0.3115 (5)0.0114 (5)
Si(7)0.1737 (4)0.4250 (4)0.3190 (6)0.0114 (5)
Si(8)0.1250 (4)0.3098 (4)0.1726 (6)0.0114 (5)
Si(9)0.1782 (4)0.2730 (4)0.0389 (5)0.0114 (5)
Si(10)0.1777 (4)0.1193 (5)0.0334 (6)0.0114 (5)
Si(11)0.1267 (4)0.0715 (4)0.1714 (6)0.0114 (5)
Si(12)0.1596 (3)0.1897 (4)0.3167 (6)0.0114 (5)
Si(13)0.4458 (4)0.4303 (4)0.3369 (6)0.0114 (5)
Si(14)0.4775 (4)0.3144 (4)0.1889 (6)0.0114 (5)
Si(15)0.4395 (4)0.2742 (4)0.0222 (5)0.0114 (5)
Si(16)0.4358 (4)0.1202 (4)0.0417 (6)0.0114 (5)
Si(17)0.4739 (4)0.0732 (5)0.1745 (6)0.0114 (5)
Si(18)0.4365 (3)0.1871 (4)0.3115 (6)0.0114 (5)
Si(19)0.6710 (4)0.4237 (4)0.3098 (6)0.0114 (5)
Si(20)0.6341 (4)0.3099 (4)0.1709 (6)0.0114 (5)
Si(21)0.6646 (4)0.2738 (4)0.0454 (6)0.0114 (5)
Si(22)0.6685 (4)0.1203 (4)0.0347 (6)0.0114 (5)
Si(23)0.6333 (4)0.0714 (4)0.1818 (6)0.0114 (5)
Si(24)0.6840 (3)0.1956 (4)0.2963 (5)0.0114 (5)
O(1)0.0619 (6)0.3829 (5)0.2232 (8)0.0134 (4)
O(2)0.0636 (5)0.3100 (7)0.0528 (5)0.0134 (4)
O(3)0.0470 (5)0.2036 (4)0.0447 (8)0.0134 (4)
O(4)0.0718 (6)0.1068 (6)0.0806 (7)0.0134 (4)
O(5)0.0444 (6)0.1260 (5)0.2700 (8)0.0134 (4)
O(6)0.0519 (6)0.2500 (5)0.2169 (8)0.0134 (4)
O(7)0.1567 (6)0.3732 (5)0.2300 (8)0.0134 (4)
O(8)0.1703 (5)0.2947 (6)0.0763 (6)0.0134 (4)
O(9)0.1555 (5)0.1963 (4)0.0302 (8)0.0134 (4)
O(10)0.1741 (6)0.0909 (6)0.0791 (7)0.0134 (4)
O(11)0.1511 (6)0.1184 (5)0.2627 (7)0.0134 (4)
O(12)0.1264 (6)0.2472 (5)0.2479 (8)0.0134 (4)
O(13)0.0470 (4)0.3236 (6)0.1450 (8)0.0134 (4)
O(14)0.0479 (4)0.0859 (6)0.1505 (9)0.0134 (4)
O(15)0.1359 (4)0.4230 (5)0.3771 (7)0.0134 (4)
O(16)0.0015 (5)0.3862 (6)0.3810 (7)0.0134 (4)
O(17)0.1352 (5)0.4090 (6)0.4215 (7)0.0134 (4)
O(18)0.1308 (4)0.2066 (6)0.3499 (7)0.0134 (4)
O(19)0.0025 (5)0.2116 (6)0.4035 (7)0.0134 (4)
O(20)0.1256 (4)0.1944 (7)0.4251 (7)0.0134 (4)
O(21)0.0486 (6)0.0036 (4)0.2113 (9)0.0134 (4)
O(22)0.1425 (6)0.0026 (4)0.2111 (8)0.0134 (4)
O(23)0.2526 (4)0.4293 (6)0.3478 (8)0.0134 (4)
O(24)0.2391 (3)0.2036 (6)0.3310 (8)0.0134 (4)
O(25)0.2560 (4)0.2763 (6)0.0710 (8)0.0134 (4)
O(26)0.2541 (4)0.1160 (7)0.0721 (8)0.0134 (4)
O(27)0.4592 (6)0.3852 (5)0.2389 (7)0.0134 (4)
O(28)0.4584 (5)0.3196 (5)0.0725 (6)0.0134 (4)
O(29)0.4292 (5)0.1957 (4)0.0025 (8)0.0134 (4)
O(30)0.4461 (6)0.0820 (6)0.0628 (6)0.0134 (4)
O(31)0.4288 (5)0.1200 (5)0.2468 (8)0.0134 (4)
O(32)0.4405 (6)0.2513 (5)0.2394 (9)0.0134 (4)
O(33)0.6676 (6)0.3775 (5)0.2115 (7)0.0134 (4)
O(34)0.6418 (5)0.3167 (5)0.0512 (6)0.0134 (4)
O(35)0.6441 (5)0.1967 (4)0.0315 (7)0.0134 (4)
O(36)0.6588 (6)0.0785 (6)0.0673 (6)0.0134 (4)
O(37)0.6726 (6)0.1212 (5)0.2551 (8)0.0134 (4)
O(38)0.6750 (6)0.2439 (5)0.2013 (8)0.0134 (4)
O(39)0.5562 (3)0.2969 (6)0.2002 (8)0.0134 (4)
O(40)0.5536 (4)0.0868 (6)0.1830 (9)0.0134 (4)
O(41)0.3761 (5)0.4211 (6)0.3987 (8)0.0134 (4)
O(42)0.5025 (5)0.4190 (6)0.4199 (7)0.0134 (4)
O(43)0.6317 (5)0.3909 (6)0.4040 (8)0.0134 (4)
O(44)0.3669 (4)0.1925 (7)0.3744 (7)0.0134 (4)
O(45)0.5021 (4)0.1801 (5)0.3802 (6)0.0134 (4)
O(46)0.6346 (5)0.2119 (6)0.3899 (7)0.0134 (4)
O(47)0.4625 (6)0.0041 (5)0.2021 (8)0.0134 (4)
O(48)0.6448 (6)0.0041 (4)0.2182 (9)0.0134 (4)
Bond lengths (Å) top
Si(1)—O(1/15/16)1.611 (1)Si(13)—O(27/41/42)1.610 (1)
Si(2)—O(1/2/6/13)1.610 (1)Si(14)—O(27/28/32/39)1.609 (1)
Si(3)—O(2/3)1.609 (1)Si(15)—O(29/29)1.609 (1)
Si(4)—O(3/4)1.610 (1)Si(16)—O(29/30)1.609 (1)
Si(5)—O(4/5/14/21)1.609 (1)Si(17)—O(30/31)1.610 (1)
Si(6)—O(5/6/18/19)1.610 (1)Si(18)—O(31/32/44/45)1.609 (1)
Si(7)—O(7/17/23)1.610 (1)Si(19)—O(33/43)1.610 (1)
Si(8)—O(7/8/12/13)1.609 (1)Si(20)—O(33/34/38/39)1.609 (1)
Si(9)—O(8/9/25)1.610 (1)Si(21)—O(34/35)1.610 (1)
Si(10)—O(9/10/26)1.610 (1)Si(22)—O(35/36)1.610 (1)
Si(11)—O(10/11/14)1.610 (1)Si(23)—O(36/37/40/48)1.610 (1)
Si(12)—O(11/12/20/24)1.610 (1)Si(24)—O(27/38/46)1.610 (1)
 

Subscribe to Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials

The full text of this article is available to subscribers to the journal.

If you have already registered and are using a computer listed in your registration details, please email support@iucr.org for assistance.

Buy online

You may purchase this article in PDF and/or HTML formats. For purchasers in the European Community who do not have a VAT number, VAT will be added at the local rate. Payments to the IUCr are handled by WorldPay, who will accept payment by credit card in several currencies. To purchase the article, please complete the form below (fields marked * are required), and then click on `Continue'.
E-mail address* 
Repeat e-mail address* 
(for error checking) 

Format*   PDF (US $40)
   HTML (US $40)
   PDF+HTML (US $50)
In order for VAT to be shown for your country javascript needs to be enabled.

VAT number 
(non-UK EC countries only) 
Country* 
 

Terms and conditions of use
Contact us

Follow Acta Cryst. B
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds