Zn vapor at 480°C reduced all Cd 2+ ions, and some Si 4+ ions, in a single crystal of fully dehyd... more Zn vapor at 480°C reduced all Cd 2+ ions, and some Si 4+ ions, in a single crystal of fully dehydrated fully Cd 2+ -exchanged zeolite X (Cd 46 Si 100 Al 92 O 384 per unit cell). The product crystal has the approximate unit-cell composition Zn 64 Si 96 Al 96 O 384 ‚7SiO 4 4-,1AlO 4 5-(a 0 ) 24.713(3) Å). The other products, Cd(g) and Si(s), left the crystal. Its structure was determined by X-ray diffraction in the cubic space group Fd3 h. Of the approximately 64 Zn 2+ ions per unit cell, 57 are in the sodalite units (28 at site I′, 23 at site II′, and six on 2-fold axes opposite four-rings), and seven are at site II in the supercage. Seven orthosilicate ions and one orthoaluminate ion fill the eight sodalite units per unit cell. Some units of zeolite framework structure must have "dissolved" to provide these ions; the remaining framework structure must be enriched in aluminum, and cavern formation is proposed. Most orthosilicate oxygen atoms bridge between a Zn 2+ ion at site I′ (1.91 Å) and another at site II′ (2.08 Å) and lie in its Zn 2+ , Zn 2+ , Si 4+ plane; each of these Zn 2+ ions coordinates tetrahedrally to three framework and one orthosilicate oxygen atom. Each orthoaluminate ion coordinates symmetrically to six Zn 2+ ions which lie on 2-fold axes; each of these Zn 2+ ions coordinates tetrahedrally to two framework and two orthoaluminate oxygen atoms.
Ronneburgite is a new chain vanadate mineral from Ronneburg, Thuringia, Germany. It occurs as red... more Ronneburgite is a new chain vanadate mineral from Ronneburg, Thuringia, Germany. It occurs as reddish-brown crystals of equant, flattened, or short prismatic habit, up to 0.5 mm in length. The crystals have an adamantine luster and are translucent. Ronneburgite is biaxial negative with refractive indices n α = 1.925(5), n β = 1.960(10), n γ = 1.988(4), and 2V x = 82°. Electron microprobe analysis (K 2 O = 16.93, MnO = 12.44, MgO = 0.62, V 2 O 5 = 68.54; total = 98.53 wt%) gives the empirical formula K 1.91 Mn 0.93 Mg 0.08 V 4.00 O 11.96 , which simplifies to K 2 MnV 4 O 12 . Ronneburgite is monoclinic, space group P2 1 /n, with a = 8.183(3), b = 9.247(3), c = 8.651(2) Å, and β = 109.74(2)°. The measured density is 2.84 g/cm 3 ; the calculated density for Z = 2 is 2.85 g/cm 3 . Single-crystal X-ray structure determination (R 1 = 0.046 for 1846 reflections) shows that ronneburgite contains infinite vierer-single metavanadate chains [(VO 3 ) n ] nof corner-sharing VO 4 tetrahedra along [101]. Although the empirical formula and calculated bond valences indicate that V is 5+ and Mn is 2+, the crystal color, a "poor" structural compatibility index, and Mn-O distances between those expected for Mn 2+ -O and Mn 3+ -O indicate that some Mn 3+ and V 4+ ions are present. K + ions and octahedral Mn n+ ions bridge between the metavanadate chains by coordinating to their oxygen atoms.
The sorption of Zn vapor at 480 C onto fully dehydrated fully Cd{sup 2+}-exchanged zeolite X (Cdâ... more The sorption of Zn vapor at 480 C onto fully dehydrated fully Cd{sup 2+}-exchanged zeolite X (CdââSiâââAlââOâââ per unit cell) has been studied at 23 C by single-crystal X-ray diffraction in the cubic space group Fd3 (aâ = 24.895(3) â«). In this structure, CdââSiâââAlââOâââ·20Zn, Cd{sup 2+} ions are found at five nonequivalent sites, redistributed significantly from 16, 0, 30, 0,
The products of the reaction of Zn vapor with fully dehydrated fully Tl + -exchanged zeolite X (T... more The products of the reaction of Zn vapor with fully dehydrated fully Tl + -exchanged zeolite X (Tl 92 Si 100 -Al 92 O 384 per unit cell) at 450°C (crystal 1, a 0 ) 24.825(3) Å, Tl + 62 Zn + 30 Si 100 Al 92 O 384 ‚2Tl 0 ,15Zn 0 ) and 500°C (crystal 2, a 0 ) 24.950(4) Å, Tl + 18 Zn 2+ 46 Si 98 Al 94 O 384 ‚4SiO 4 4-) have been studied by single-crystal X-ray diffraction in the cubic space groups Fd3 hm and Fd3 h, respectively. In crystal 1, 30 Tl + ions were reduced by Zn(g) and replaced by Zn + ions (18 are found at site I′ and 12 at site II′). This is the first report of the monatomic cation Zn + . Some of the product Tl atoms and additional Zn(g) atoms were captured by some of the remaining site-II Tl + ions possibly to form (sparsely) Tl + 4 Zn 0 12 Tl 0 4 clusters of symmetry 4 h3m at supercage centers. This cluster has a central Tl 4 tetrahedron surrounded by 12 Zn atoms, surrounded by four Tl + ions (a third shell), all in a cubic closest-packed arrangement. Other Tl + ions have captured Zn atoms, perhaps to form smaller clusters. The Tl + populations at the III′ sites were unaffected by this reaction. In crystal 2, the desired redox reaction of Zn(g) with Tl + has gone most of the way to completion. Almost all Tl + ions at sites I′ and II, and 12 of the 28 at III′ sites, have been replaced by Zn 2+ at sites I′, II′, and II. An orthosilicate ion (aluminate less likely) is found at the centers of half of the sodalite units. Each orthosilicate oxygen bridges between a Zn 2+ ion at site I′ (2.11 Å) and another at site II′ (2.17 Å) and lies in its Zn 2+ , Zn 2+ , Si 4+ plane. A formally neutral octahedral Tl 6 cluster, supported by coordination to Zn 2+ cations, appears to center some sodalite cavities.
Zn vapor at 480°C reduced all Cd 2+ ions, and some Si 4+ ions, in a single crystal of fully dehyd... more Zn vapor at 480°C reduced all Cd 2+ ions, and some Si 4+ ions, in a single crystal of fully dehydrated fully Cd 2+ -exchanged zeolite X (Cd 46 Si 100 Al 92 O 384 per unit cell). The product crystal has the approximate unit-cell composition Zn 64 Si 96 Al 96 O 384 ‚7SiO 4 4-,1AlO 4 5-(a 0 ) 24.713(3) Å). The other products, Cd(g) and Si(s), left the crystal. Its structure was determined by X-ray diffraction in the cubic space group Fd3 h. Of the approximately 64 Zn 2+ ions per unit cell, 57 are in the sodalite units (28 at site I′, 23 at site II′, and six on 2-fold axes opposite four-rings), and seven are at site II in the supercage. Seven orthosilicate ions and one orthoaluminate ion fill the eight sodalite units per unit cell. Some units of zeolite framework structure must have "dissolved" to provide these ions; the remaining framework structure must be enriched in aluminum, and cavern formation is proposed. Most orthosilicate oxygen atoms bridge between a Zn 2+ ion at site I′ (1.91 Å) and another at site II′ (2.08 Å) and lie in its Zn 2+ , Zn 2+ , Si 4+ plane; each of these Zn 2+ ions coordinates tetrahedrally to three framework and one orthosilicate oxygen atom. Each orthoaluminate ion coordinates symmetrically to six Zn 2+ ions which lie on 2-fold axes; each of these Zn 2+ ions coordinates tetrahedrally to two framework and two orthoaluminate oxygen atoms.
The review presents and discusses the most reliable and detailed structural reports of organic mo... more The review presents and discusses the most reliable and detailed structural reports of organic molecules in zeolites A, X, Y, ZSM-5, and ferrierite. The energetics responsible for the sorption of organic molecules into zeolites is discussed, and the general principles for the selection by organic molecules of sorption sites within a zeolite are outlined. Ó
Zn vapor at 480°C reduced all Cd 2+ ions, and some Si 4+ ions, in a single crystal of fully dehyd... more Zn vapor at 480°C reduced all Cd 2+ ions, and some Si 4+ ions, in a single crystal of fully dehydrated fully Cd 2+ -exchanged zeolite X (Cd 46 Si 100 Al 92 O 384 per unit cell). The product crystal has the approximate unit-cell composition Zn 64 Si 96 Al 96 O 384 ‚7SiO 4 4-,1AlO 4 5-(a 0 ) 24.713(3) Å). The other products, Cd(g) and Si(s), left the crystal. Its structure was determined by X-ray diffraction in the cubic space group Fd3 h. Of the approximately 64 Zn 2+ ions per unit cell, 57 are in the sodalite units (28 at site I′, 23 at site II′, and six on 2-fold axes opposite four-rings), and seven are at site II in the supercage. Seven orthosilicate ions and one orthoaluminate ion fill the eight sodalite units per unit cell. Some units of zeolite framework structure must have "dissolved" to provide these ions; the remaining framework structure must be enriched in aluminum, and cavern formation is proposed. Most orthosilicate oxygen atoms bridge between a Zn 2+ ion at site I′ (1.91 Å) and another at site II′ (2.08 Å) and lie in its Zn 2+ , Zn 2+ , Si 4+ plane; each of these Zn 2+ ions coordinates tetrahedrally to three framework and one orthosilicate oxygen atom. Each orthoaluminate ion coordinates symmetrically to six Zn 2+ ions which lie on 2-fold axes; each of these Zn 2+ ions coordinates tetrahedrally to two framework and two orthoaluminate oxygen atoms.
Ronneburgite is a new chain vanadate mineral from Ronneburg, Thuringia, Germany. It occurs as red... more Ronneburgite is a new chain vanadate mineral from Ronneburg, Thuringia, Germany. It occurs as reddish-brown crystals of equant, flattened, or short prismatic habit, up to 0.5 mm in length. The crystals have an adamantine luster and are translucent. Ronneburgite is biaxial negative with refractive indices n α = 1.925(5), n β = 1.960(10), n γ = 1.988(4), and 2V x = 82°. Electron microprobe analysis (K 2 O = 16.93, MnO = 12.44, MgO = 0.62, V 2 O 5 = 68.54; total = 98.53 wt%) gives the empirical formula K 1.91 Mn 0.93 Mg 0.08 V 4.00 O 11.96 , which simplifies to K 2 MnV 4 O 12 . Ronneburgite is monoclinic, space group P2 1 /n, with a = 8.183(3), b = 9.247(3), c = 8.651(2) Å, and β = 109.74(2)°. The measured density is 2.84 g/cm 3 ; the calculated density for Z = 2 is 2.85 g/cm 3 . Single-crystal X-ray structure determination (R 1 = 0.046 for 1846 reflections) shows that ronneburgite contains infinite vierer-single metavanadate chains [(VO 3 ) n ] nof corner-sharing VO 4 tetrahedra along [101]. Although the empirical formula and calculated bond valences indicate that V is 5+ and Mn is 2+, the crystal color, a "poor" structural compatibility index, and Mn-O distances between those expected for Mn 2+ -O and Mn 3+ -O indicate that some Mn 3+ and V 4+ ions are present. K + ions and octahedral Mn n+ ions bridge between the metavanadate chains by coordinating to their oxygen atoms.
The sorption of Zn vapor at 480 C onto fully dehydrated fully Cd{sup 2+}-exchanged zeolite X (Cdâ... more The sorption of Zn vapor at 480 C onto fully dehydrated fully Cd{sup 2+}-exchanged zeolite X (CdââSiâââAlââOâââ per unit cell) has been studied at 23 C by single-crystal X-ray diffraction in the cubic space group Fd3 (aâ = 24.895(3) â«). In this structure, CdââSiâââAlââOâââ·20Zn, Cd{sup 2+} ions are found at five nonequivalent sites, redistributed significantly from 16, 0, 30, 0,
The products of the reaction of Zn vapor with fully dehydrated fully Tl + -exchanged zeolite X (T... more The products of the reaction of Zn vapor with fully dehydrated fully Tl + -exchanged zeolite X (Tl 92 Si 100 -Al 92 O 384 per unit cell) at 450°C (crystal 1, a 0 ) 24.825(3) Å, Tl + 62 Zn + 30 Si 100 Al 92 O 384 ‚2Tl 0 ,15Zn 0 ) and 500°C (crystal 2, a 0 ) 24.950(4) Å, Tl + 18 Zn 2+ 46 Si 98 Al 94 O 384 ‚4SiO 4 4-) have been studied by single-crystal X-ray diffraction in the cubic space groups Fd3 hm and Fd3 h, respectively. In crystal 1, 30 Tl + ions were reduced by Zn(g) and replaced by Zn + ions (18 are found at site I′ and 12 at site II′). This is the first report of the monatomic cation Zn + . Some of the product Tl atoms and additional Zn(g) atoms were captured by some of the remaining site-II Tl + ions possibly to form (sparsely) Tl + 4 Zn 0 12 Tl 0 4 clusters of symmetry 4 h3m at supercage centers. This cluster has a central Tl 4 tetrahedron surrounded by 12 Zn atoms, surrounded by four Tl + ions (a third shell), all in a cubic closest-packed arrangement. Other Tl + ions have captured Zn atoms, perhaps to form smaller clusters. The Tl + populations at the III′ sites were unaffected by this reaction. In crystal 2, the desired redox reaction of Zn(g) with Tl + has gone most of the way to completion. Almost all Tl + ions at sites I′ and II, and 12 of the 28 at III′ sites, have been replaced by Zn 2+ at sites I′, II′, and II. An orthosilicate ion (aluminate less likely) is found at the centers of half of the sodalite units. Each orthosilicate oxygen bridges between a Zn 2+ ion at site I′ (2.11 Å) and another at site II′ (2.17 Å) and lies in its Zn 2+ , Zn 2+ , Si 4+ plane. A formally neutral octahedral Tl 6 cluster, supported by coordination to Zn 2+ cations, appears to center some sodalite cavities.
Zn vapor at 480°C reduced all Cd 2+ ions, and some Si 4+ ions, in a single crystal of fully dehyd... more Zn vapor at 480°C reduced all Cd 2+ ions, and some Si 4+ ions, in a single crystal of fully dehydrated fully Cd 2+ -exchanged zeolite X (Cd 46 Si 100 Al 92 O 384 per unit cell). The product crystal has the approximate unit-cell composition Zn 64 Si 96 Al 96 O 384 ‚7SiO 4 4-,1AlO 4 5-(a 0 ) 24.713(3) Å). The other products, Cd(g) and Si(s), left the crystal. Its structure was determined by X-ray diffraction in the cubic space group Fd3 h. Of the approximately 64 Zn 2+ ions per unit cell, 57 are in the sodalite units (28 at site I′, 23 at site II′, and six on 2-fold axes opposite four-rings), and seven are at site II in the supercage. Seven orthosilicate ions and one orthoaluminate ion fill the eight sodalite units per unit cell. Some units of zeolite framework structure must have "dissolved" to provide these ions; the remaining framework structure must be enriched in aluminum, and cavern formation is proposed. Most orthosilicate oxygen atoms bridge between a Zn 2+ ion at site I′ (1.91 Å) and another at site II′ (2.08 Å) and lie in its Zn 2+ , Zn 2+ , Si 4+ plane; each of these Zn 2+ ions coordinates tetrahedrally to three framework and one orthosilicate oxygen atom. Each orthoaluminate ion coordinates symmetrically to six Zn 2+ ions which lie on 2-fold axes; each of these Zn 2+ ions coordinates tetrahedrally to two framework and two orthoaluminate oxygen atoms.
The review presents and discusses the most reliable and detailed structural reports of organic mo... more The review presents and discusses the most reliable and detailed structural reports of organic molecules in zeolites A, X, Y, ZSM-5, and ferrierite. The energetics responsible for the sorption of organic molecules into zeolites is discussed, and the general principles for the selection by organic molecules of sorption sites within a zeolite are outlined. Ó
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