Inorganic structures in space group P31m; coordinate analysis and systematic prediction of new ferroelectrics

2010 ◽  
Vol 66 (2) ◽  
pp. 173-183 ◽  
Author(s):  
S. C. Abrahams
Keyword(s):  
Crystal Structures ◽  
Aluminum Sulfate ◽  
Polar Space ◽  
Candidate Selection ◽  
Primary Sources ◽  
Structural Determination ◽  
Space Group ◽  
Sources Of Uncertainty ◽  
Upper Limit ◽  
Inorganic Crystal

The 62 entries listed in ICSD release 2009/1 under polar space group P31m correspond to 31 families of inorganic crystal structures, some with only one member. Coordinate analysis reveals, over a wide confidence range, 11 of these families as ferroelectric candidates. One includes the well known improper ferroelectric GASH (guanidinium aluminum sulfate hexahydrate), [(C(NH2)3)Al(SO4)2(H2O)6], another the previously predicted ferroelectric CsNO3 phase II. Those remaining include K3Nb3B2O12, the minerals schairerite, galeite and lizardite 1T, LaNi5D6 and γ-CaNi5D6.1, Ca(OCl)2Ca(OH)2, [N(CH3)4]2Mo3S13, Li17Ag3Sn6 and Cs3As5O9. Candidate selection is based upon detecting an approach by the reported atomic arrangement to the symmetry of a corresponding nonpolar supergroup. A further 13 families are typified by their reduced predictive properties, with four others likely to remain polar at higher temperatures and the remaining three noted as having a unit cell larger than reported or a misassigned space group. The primary sources of uncertainty in structurally based predictions of ferroelectricity are the reliability of the underlying structural determination and the upper limit assigned to the cationic displacement magnitudes required to achieve supergroup symmetry.

Inorganic structures in space group P3m1; coordinate analysis and systematic prediction of new ferroelectrics

2008 ◽  
Vol 64 (4) ◽  
pp. 426-437 ◽  
Author(s):  
S. C. Abrahams
Keyword(s):  
Crystal Structures ◽  
Primary Source ◽  
Polar Space ◽  
Structural Determination ◽  
Space Group ◽  
Atomic Arrangement ◽  
Thermal Range ◽  
Confidence Levels ◽  
Inorganic Crystal

ICSD Release 2007/1 contains 47 families of inorganic crystal structures, some single-member only, within the 311 entries listed under the polar space group P3m1. Coordinate analysis reveals 12 such families to be candidate ferroelectrics, over a range of confidence levels. Selection is based on the detection of an approach to nonpolar supergroup symmetry, within specified limits, by the atomic arrangement as reported in a confirmed polar space group. The primary source of uncertainty in such predictions is the reliability of the underlying structural determination. The candidates include In2ZnS4, TlSn2F5, Cu7Te4, NaMnSe2, Na2In2(Mo3O8)(MoO4)2, Nb3Br7S, Nb3TeI7, fencooperite, Bi(HCOO)3, Li(NpO2)(CO3)(H2O)2, LiPtD0.66 and Ag3(MoO3F3)(Ag3(MoO4)Cl). A total of 20 structures examined are likely to be nonpolar, a further 20 have reduced predictive properties and three others are more likely to retain P3m1 symmetry over a wide thermal range. Substantial uncertainties associated with many of the listed 163 CdI2, 69 ZnS and 10 SiC polytype structures, together with their low potential for use as possible ferroelectrics, led to their exclusion from fuller analysis.

Systematic prediction of new ferroelectrics in space group P3

2000 ◽  
Vol 56 (5) ◽  
pp. 793-804 ◽  
Author(s):  
S. C. Abrahams
Keyword(s):  
Crystal Structure ◽  
Confidence Level ◽  
Inorganic Crystal Structure Database ◽  
Structural Determination ◽  
Structural Studies ◽  
Space Group ◽  
Structure Database ◽  
Inorganic Crystal ◽  
Atomic Coordinates ◽  
Crystal Structure Database

The current release of the Inorganic Crystal Structure Database contains a total of 57 entries under space group P3 that correspond to 50 different materials. There are 21 structures reported with this space group that satisfy the criteria for ferroelectricity, at a confidence level that depends on the reliability of the underlying structural determination. One ferroelectric discovered earlier is also listed. In addition, the database contains 19 entries that probably should be assigned to a centrosymmetric space group, seven that are polar but probably not ferroelectric and two that are without atomic coordinates. Seven entries are either duplicates or present additional structural studies of the same material. Structures in space group P3 identified as potentially new ferroelectrics include LiAsCu0.93, Na2UF6, BiTeI, BaGe4O9, α-UMo2O8, Cu2SiS3, Co(IO3)2, Sr7Al12O25, KSn2F5, YbIn2S4, Na5CrF2(PO4)2, Sn(ClO2)2(ClO4)6, Eu3BWO9, Li(H2O)4B(OH)4·2H2O, Mn3V1/2(SiO4)O(OH)2, Ca6(Si2O7)(OH)6, Na6.9(2)[Al5.6(1)Si6.4(1)O24](S2O3)1.0(1)·2H2O, BaCa2In6O12, Ni(H2O)6[Sb(OH)6]2, Sr4Cr3O9 and Cu5O2(VO4)2·CuCl2.

Ln3 M 1 − δ TX 7 – quasi-isostructural compounds: stereochemistry and silver-ion motion in the Ln3Ag1 − δGeS7 (Ln = La–Nd, Sm, Gd–Er and Y; δ = 0.11–0.50) compounds

2009 ◽  
Vol 65 (2) ◽  
pp. 126-133 ◽  
Author(s):  
Marek Daszkiewicz ◽  
Lubomir D. Gulay ◽  
Olga S. Lychmanyuk
Keyword(s):  
Crystal Structures ◽  
Large Family ◽  
Silver Ions ◽  
Structural Effect ◽  
Inorganic Crystal Structure Database ◽  
Single Crystal Diffraction ◽  
Ion Motion ◽  
Space Group ◽  
Inorganic Crystal ◽  
Crystal Structure Database

The crystal structures of the Ln3Ag1 − δGeS7 (Ln = La–Nd, Sm, Gd–Er, Y; δ = 0.11–0.50, space group P63) compounds were determined by means of X-ray single-crystal diffraction and the similarities among the crystal structures of all Ln3 M 1 − δ TX 7 (space group P63; Ln – lanthanide element, M – monovalent element; T – tetravalent element and X – S, Se) compounds deposited in the Inorganic Crystal Structure Database (ICSD) are discussed. Substitutions of each element in Ln3 M 1 − δ TX 7 result in a different structural effect. On the basis of the data deposited in the ICSD the large family of the Ln3 M 1 − δ TX 7 compounds was divided into three groups depending on the position of the monovalent element in the lattice. This position determines what kind of stereoisomer is present in the structure, either the ++ enantiomer or the +− diastereoisomer. Since the silver ions can occupy a different position and the energy barriers between positions are low the ions can move through the channel. It was shown that this movement is not a stochastic process but a correlated one.

Manifestations of noncovalent interactions in the solid state. 3. X-ray crystal structures of [H4(cyclam)][FeCl5(OH2)](Cl)2 and [H4(cyclam)][CF3COO]4, two network hydrogen bonded solids

1993 ◽  
Vol 71 (4) ◽  
pp. 433-440 ◽  
Author(s):  
S. Subramanian ◽  
Michael J. Zaworotko
Keyword(s):  
Hydrogen Bonding ◽  
Crystal Structures ◽  
Rational Design ◽  
Complex Anion ◽  
Noncovalent Interactions ◽  
Polar Space ◽  
Space Group ◽  
X Ray ◽  
Dark Orange ◽  
Interionic Hydrogen

FeCl2 or FeCl3 react with cyclam (cyclam = 1,4,8,11-tetraazacyclotetradecane) in an acidic medium (4 M HCl) to afford dark orange-red plates of [H4(cyclam)][FeCl5(OH2)](Cl)2 (1). 1 crystallizes in a polar space group (orthorhombic, Pc21b) with a = 10.7730(6), b = 13.3418(10), c = 14.4564(10) Å, V = 2077.84(24) Å3, and Dcalc = 1.68 g cm−3 for Z = 4. Final values of R = 0.031 and Rw = 0.034 were obtained for 1950 independent observed (I > 3σ(I)) reflections. Cyclam reacts with neat trifluoroacetic acid to afford a colourless salt, [H4(cyclam)][CF3COO]4 (2). 2 crystallizes in a centric space group (monoclinic, P21/c), with a = 8.7442(11), b = 10.5121(11), c = 15.2469(20) Å, β = 102.526(15)°, V = 1368.1(3) Å3, and Dcalc = 1.593 g cm−3 for Z = 2. Final values of R = 0.059 and Rw = 0.067 were obtained for 1336 independent observed (I > 3σ(I)) reflections. Extensive interionic hydrogen bonding between the cyclam cations, which adopt exodentate conformations, and anions results in network polymeric hydrogen bonding (1-D for 1, 2-D for 2). The networking in 1 is intrinsically polar because one chloride anion and the [FeCl5(OH2)]2− complex anion are involved in networking between the H4(cyclam)4+ cations. The implications of the crystal structures are discussed from the perspective of rational design of polar solids.

scholarly journals Crystal-to-Crystal Transformation from K2[Co(C2O4)2(H2O)2]·4H2O to K2[Co(μ-C2O4)(C2O4)]

2021 ◽  
Vol 7 (6) ◽  
pp. 77
Author(s):  
Bin Zhang ◽  
Yan Zhang ◽  
Guangcai Chang ◽  
Zheming Wang ◽  
Daoben Zhu
Keyword(s):  
Hydrogen Bond ◽  
Physical Properties ◽  
Crystal Structures ◽  
Molecular Crystal ◽  
Trigonal Prism ◽  
Space Group ◽  
Cell Parameters ◽  
Oxalate Anion ◽  
Crystal Transformation ◽  
Antiferromagnetic Ordering

Crystal-to-crystal transformation is a path to obtain crystals with different crystal structures and physical properties. K2[Co(C2O4)2(H2O)2]·4H2O (1) is obtained from K2C2O4·2H2O, CoCl2·6H2O in H2O with a yield of 60%. It is crystallized in the triclinic with space group P1 and cell parameters: a = 7.684(1) Å, b = 9.011(1) Å, c = 10.874(1) Å, α = 72.151(2)°, β = 70.278(2)°, γ = 80.430(2)°, V = 670.0(1) Å3, Z = 2 at 100 K. 1 is composed of K+, mononuclear anion [Co(C2O4)2(H2O)22−] and H2O. Co2+ is coordinated by two bidentated oxalate anion and two H2O in an octahedron environment. There is a hydrogen bond between mononuclear anion [Co(C2O4)2(H2O)22−] and H2O. K2[Co(μ-C2O4)(C2O4)] (2) is obtained from 1 by dehydration. The cell parameters of 2 are a = 8.460(5) Å, b = 6.906 (4) Å, c = 14.657(8) Å, β = 93.11(1)°, V = 855.0(8) Å3 at 100 K, with space group in P2/c. It is composed of K+ and zigzag [Co(μ-C2O4)(C2O42−]n chain. Co2+ is coordinated by two bisbendentate oxalate and one bidentated oxalate anion in trigonal-prism. 1 is an antiferromagnetic molecular crystal. The antiferromagnetic ordering at 8.2 K is observed in 2.

A plastically bendable and polar organic crystal

CrystEngComm ◽  
2021 ◽  
Author(s):  
Sotaro Kusumoto ◽  
Akira Sugimoto ◽  
Daisuke Kosumi ◽  
Yang Kim ◽  
Yoshihiro Sekine ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Polar Space ◽  
Organic Crystal ◽  
Space Group ◽  
High Dielectric

In this communication, an organic crystal of the polar space group Pc that is capable of plastically bending in response to external mechanical stress is reported, and its high dielectric...

Synthesis and Crystal Structures of Three Carboxylate- Bridged Tetranuclear Copper(II) - Lanthanide(III) Complexes of Ph3P+CH2CH2CO2−

1999 ◽  
Vol 52 (10) ◽  
pp. 983 ◽  
Author(s):  
Yang-Yi Yang ◽  
Seik Weng Ng ◽  
Xiao-Ming Chen
Keyword(s):  
Oxygen Atom ◽  
Crystal Structures ◽  
Triclinic Space Group ◽  
Coordination Environment ◽  
Space Group ◽  
Bond Angles ◽  
Bond Lengths ◽  
Metal Atoms ◽  
Apical Site

Three tetranuclear copper(II)–lanthanide(III) complexes of triphenylphosphoniopropionate (Ph3P+CH2CH2CO2−,tppp), namely [Cu2Ln2(tppp)8(H2O)8](ClO4)10·2H 2 O [Ln = EuIII, NdIII or CeIII], were synthesized and characterized by crystallography. The EuIII complex crystallizes in the triclinic space group P1 – with a 16.249(7), b 17.185(11), c 17.807(11) Å, α 69.750(10), β 89.230(10), γ 84.070(10)˚, V 4639(5) Å3, Z 1. In the crystal structures, four tppp ligands bridge a pair of CuII and tetraaquo-EuIII atoms (Cu···Eu 3.527(2) Å) through their µ2-carboxylato ends to form a dinuclear subunit; two of these subunits are additionally linked by one of the CuII -bonded carboxylato oxygen ends, across a centre of inversion, to furnish a dimeric tetranuclear [Cu(tppp)4 Eu(H2O)4]2 species (Cu···Cu 3.323(2) Å). This CuII -bonded oxygen atom occupies the apical site of the square-pyramidal coordination environment of the CuII atom. The EuIII atom is eight-coordinated in a square-antiprismatic geometry. The NdIII and CeIII complexes are isomorphous to the EuIII complex, and only minor differences in bond lengths and bond angles involving the metal atoms are noted.

Studies in aryltin chemistry. Part 6. Crystal and molecular structures of tetra(p-methylsulphonylphenyl)tin(IV) and tetra(p-methylsulphinylphenyl)tin(IV) monohydrate

1990 ◽  
Vol 68 (8) ◽  
pp. 1277-1282 ◽  
Author(s):  
Ivor Wharf ◽  
Michel G. Simard ◽  
Henry Lamparski
Keyword(s):  
Least Squares ◽  
Crystal Structures ◽  
Direct Method ◽  
Molecular Structures ◽  
Water Molecules ◽  
Monoclinic Space Group ◽  
Molecular Symmetry ◽  
Asymmetric Unit ◽  
Full Matrix ◽  
Space Group

Tetrakis(p-methylsulphonylphenyl)tin(IV) and tetrakis(p-methylsulphinylphenyl)tin(IV) n-hydrate have been prepared and their spectra (ir 1350–400 cm−1; nmr, 1H, 13C, 119Sn) and X-ray crystal structures are reported. The first compound is monoclinic, space group C2/c, Z = 4, with a = 21.589(6), b = 6.207(3), c = 22.861(11) Å, β = 93.80(3)° (22 °C); the structure was solved by the direct method and refined by full-matrix least squares calculations to R = 0.043 for 2755 observed reflections. It has 2 molecular symmetry with the methyl group and one oxygen atom completely disordered in both CH3S(O2) groups in the asymmetric unit. The second compound is tetragonal, space group P42/n, Z = 2, with a = b = 15.408(6), c = 6.379(2) Å (−100 °C); the structure was solved by the Patterson method and refined by full-matrix least squares calculations to R = 0.060 for 1209 observed reflections. It has [Formula: see text] molecular symmetry with the whole asymmetric unit disordered. Water molecules occupy positions on parallel 42 axes but molecular packing requirements prevent all sites having 100% occupancy giving n ~ 1 for the hydrate. Keywords: Tetra-aryltins, crystal structures, sulphone, sulphoxide, hydrogen-bonding.

scholarly journals New crystal structures of adenylate kinase fromStreptococcus pneumoniaeD39 in two conformations

2014 ◽  
Vol 70 (11) ◽  
pp. 1468-1471
Author(s):  
Trung Thanh Thach ◽  
Sangho Lee
Keyword(s):  
Crystal Structures ◽  
Adenylate Kinase ◽  
Bound States ◽  
Critical Role ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
Space Group ◽  
Cell Parameters ◽  
Ligand Free ◽  
Adenylate Kinases

Adenylate kinases (AdKs; EC 2.7.3.4) play a critical role in intercellular homeostasis by the interconversion of ATP and AMP to two ADP molecules. Crystal structures of adenylate kinase fromStreptococcus pneumoniaeD39 (SpAdK) have recently been determined using ligand-free and inhibitor-bound crystals belonging to space groupsP21andP1, respectively. Here, new crystal structures of SpAdK in ligand-free and inhibitor-bound states determined at 1.96 and 1.65 Å resolution, respectively, are reported. The new ligand-free crystal belonged to space groupC2, with unit-cell parametersa= 73.5,b= 54.3,c= 62.7 Å, β = 118.8°. The new ligand-free structure revealed an open conformation that differed from the previously determined conformation, with an r.m.s.d on Cαatoms of 1.4 Å. The new crystal of the complex with the two-substrate-mimicking inhibitorP1,P5-bis(adenosine-5′-)pentaphosphate (Ap5A) belonged to space groupP1, with unit-cell parametersa= 53.9,b= 62.3,c= 63.0 Å, α = 101.9, β = 112.6, γ = 89.9°. Despite belonging to the same space group as the previously reported crystal, the new Ap5A-bound crystal contains four molecules in the asymmetric unit, compared with two in the previous crystal, and shows slightly different lattice contacts. These results demonstrate that SpAdK can crystallize promiscuously in different forms and that the open structure is flexible in conformation.

Distorted chiolite crystal structures of α-Na5M3F14 (M=Cr,Fe,Ga) studied by X-ray powder diffraction

2003 ◽  
Vol 18 (2) ◽  
pp. 128-134 ◽  
Author(s):  
A. Le Bail ◽  
A.-M. Mercier
Keyword(s):  
Crystal Structures ◽  
Powder Diffraction ◽  
Room Temperature ◽  
Rietveld Refinements ◽  
Space Group ◽  
X Ray ◽  
Precise Characterization

The crystal structures of the chiolite-related room temperature phases α-Na5M3F14 (MIII=Cr,Fe,Ga) are determined. For all of them, the space group is P21/n, Z=2; a=10.5096(3) Å, b=7.2253(2) Å, c=7.2713(2) Å, β=90.6753(7)° (M=Cr); a=10.4342(7) Å, b=7.3418(6) Å, c=7.4023(6) Å, β=90.799(5)° (M=Fe), and a=10.4052(1) Å, b=7.2251(1) Å, c=7.2689(1), β=90.6640(4)° (M=Ga). Rietveld refinements produce final RF factors 0.036, 0.033, and 0.035, and RWP factors, 0.125, 0.116, and 0.096, for MIII=Cr, Fe, and Ga, respectively. The MF6 polyhedra in the defective isolated perovskite-like layers deviate very few from perfect octahedra. Subtle octahedra tiltings lead to the symmetry decrease from the P4/mnc space group adopted by the Na5Al3F14 chiolite aristotype to the P21/n space group adopted by the title series. Facile twinning precluded till now the precise characterization of these compounds.

Sign in / Sign up

Export Citation Format

Share Document