Lattice matching (LM)--prevention of inadvertent duplicate publications of crystal structures.Lattice-matching techniques have proved to be extremely effective for the identification of unknown crystalline Like a crystal. It implies a uniform structure of molecules in all dimensions. For example, phase change technology, widely used for rewritable optical discs, uses crystalline spots (bits) to reflect the laser beam. Amorphous, non-crystalline bits do not reflect light. materials. A commonly employed lattice-matching strategy is based on matching the reduced cell of an unknown against a database of known materials represented by their respective standard reduced cells. The success of the method relies on the fact that the lattice (theory) lattice - A partially ordered set in which all finite subsets have a least upper bound and greatest lower bound. This definition has been standard at least since the 1930s and probably since Dedekind worked on lattice theory in the 19th century; though he may not or the lattice plus chemical information (e.g., element types) is highly characteristic of a material--like a fingerprint fingerprint, an impression of the underside of the end of a finger or thumb, used for identification because the arrangement of ridges in any fingerprint is thought to be unique and permanent with each person (no two persons having the same prints have ever been . Because of its intrinsic intrinsic /in·trin·sic/ (in-trin´sik) situated entirely within or pertaining exclusively to a part. in·trin·sic adj. 1. Of or relating to the essential nature of a thing. 2. power, the procedure has many and diverse applications--in materials characterization A rather long and fancy word for analyzing a system or process and measuring its "characteristics." For example, a Web characterization would yield the number of current sites on the Web, types of sites, annual growth, etc. , in nano-technology, in epitaxial growth, in materials design, etc. An especially fruitful fruit·ful adj. 1. a. Producing fruit. b. Conducive to productivity; causing to bear in abundance: fruitful soil. 2. role for the method is in the journal publication process as the quality of the scientific literature can be enhanced. The focus herein is on the major role that lattice matching can play in the prevention of inadvertent duplicate DUPLICATE. The double of anything. 2. It is usually applied to agreements, letters, receipts, and the like, when two originals are made of either of them. Each copy has the same effect. publications of the same structure and in the determination of key cross-references. Key words: crystallography; identification; lattice matching; mathematical lattices; multiple publication of the same structure; reduction. 1. Introduction--Lattice Matching (LM) Lattice matching techniques have played a vital role in the identification of unknown crystalline materials. A commonly employed strategy for lattice matching (1- 3)--based on matching the reduced cell of an unknown against a database of known materials represented by their respective standard reduced cells--is summarized in Fig. 1. As the figure shows, first lattice matching is carried out and then this is followed, if necessary, by a chemical screening of the resultant This article is about the resultant of polynomials. For the result of adding two or more vectors, see Parallelogram rule. For the technique in organ building, see Resultant (organ). In mathematics, the resultant of two monic polynomials matches. (For convenience, this reduction based lattice-matching identification procedure is hereafter In the future. The term hereafter is always used to indicate a future time—to the exclusion of both the past and present—in legal documents, statutes, and other similar papers. referred to as LM.) The success of LM relies on the fact that the lattice or the lattice and chemical information (e.g., element types) uniquely defines a crystalline material--like a finger-print. LM has proved to be a simple, powerful, and an easy-to-use method to identify unknowns. Practical experience has shown that the method is highly selective--even when the identification is against a database with several hundred thousand materials. Today the scientific community routinely uses LM in the identification of unknown crystalline compounds, as the strategy has been integrated into commercial x-ray diffractometers (4). Similarly, LM--integrated into database distribution software--is routinely used in identifying unknowns against the various crystallographic crys·tal·log·ra·phy n. The science of crystal structure and phenomena. crys  tal·log databases.Because of the intrinsic power of LM to identify and characterize materials, it has many diverse applications--e.g., in nano-technology, in epitaxial growth, in materials design, etc. An especially fruitful role for LM--the focus herein--is to enhance the journal publication process in crystallography and improve the quality of the scientific literature. 2. Discussion During the experimental and publication process, it is critical to be aware of previous publications as well as contemporary work on the same or related materials. This knowledge is essential to enhance the expeditious ex·pe·di·tious adj. Acting or done with speed and efficiency. See Synonyms at fast1. ex use of previous research, thereby reducing unnecessary duplicate efforts, to optimize optimize - optimisation the information management of independent studies of the same material, and to provide key cross-references. However, inspection of the recent literature reveals that redundant efforts and inadvertent omission omission n. 1) failure to perform an act agreed to, where there is a duty to an individual or the public to act (including omitting to take care) or is required by law. Such an omission may give rise to a lawsuit in the same way as a negligent or improper act. of key cross-references are not uncommon. The following three cases demonstrate the manner in which LM can prevent such problems in the first place or resolve them after publication. 2.1 Case 1. Piperidinium Dihydrogenphosphate In 2001, a paper (5) reported the crystal structure of piperidinium dihydrogenphosphate as a "new compound." LM (Fig. 1) reveals that the compound was previously reported in the literature in 1989 (6) (see Table 1). Both structures are the same even though the original structure was reported as monoclinic mon·o·clin·ic adj. Of or relating to three unequal crystal axes, two of which intersect obliquely and are perpendicular to the third. monoclinic Adjective Crystallog and the later structure reported, incorrectly, as triclinic. This example demonstrates that LM--applied during the course of the experimental work (or the publication process) for the 2001 paper--would have identified prior work and prevented an error in symmetry symmetry, generally speaking, a balance or correspondence between various parts of an object; the term symmetry is used both in the arts and in the sciences. determination. 2.2 Case 2. N, N'-Diphenylguanidine In 1999, the structure of orthorhombic or·tho·rhom·bic adj. Of or relating to a crystalline structure of three mutually perpendicular axes of different length. orthorhombic N, N'-diphenylguanidine (8) was reported as a "new crystal structure." LM reveals that this structure was previously reported in the literature in 1998 (9) (see Table 2). The later paper does not reference the earlier publication even though the structures are identical. In this case, however, most of the research for the later paper may have been carried out prior to the appearance in print of the 1998 paper. Cases like this are not uncommon because crystallographic data are published in such diverse fields and journals, and often it is especially difficult to find relevant recent publications. (Consequently, as a side issue, it would be useful to develop some mechanism so researchers can readily locate recent and concurrent work on a specified crystal structure.) 2.3 Case 3. 1,8-Terpin It is not uncommon for a compound to be reported to be spoken of; to be mentioned, whether favorably or unfavorably. See also: Report in a space group having too low symmetry. Fortunately, such errors are periodically located and corrected in the scientific literature. Accordingly, this was done (10) for an incorrect determination of 1,8-terpin (11). This case, however, illustrates a trap because the focus was to correct the incorrect structure without realizing that the correct structure already had been published (12). LM reveals that five papers report data on 1,8-terpin--two with lattice data only and three with full structure determinations. The lattice parameters for the three full structure determinations (10-12) are given in chronological chron·o·log·i·cal also chron·o·log·ic adj. 1. Arranged in order of time of occurrence. 2. Relating to or in accordance with chronology. order (left to right) in Table 3. Note that for Lattice II, the compound is described in a C-centered monoclinic space group. However, inspection of Table 3, reveals that the reduced form In social science and statistics, particularlly econometrics, a reduced form equation is a method of dealing with endogeneity. A reduced form equation is defined by James Stock & Mark Watson (2007) in the following way: (reduced form number = 16) corresponds to an F-centered orthorhombic lattice. In the final study (Lattice III), Marsh and Herbstein correct the symmetry assigned as·sign tr.v. as·signed, as·sign·ing, as·signs 1. To set apart for a particular purpose; designate: assigned a day for the inspection. 2. to Lattice II and refine the structure in the F-centered orthorhombic lattice. It is instructive in·struc·tive adj. Conveying knowledge or information; enlightening. in·struc  tive·ly adv. to
note that the authors of the second (11) and third (10) determinations
do not reference the first (12) determination, which was originally
correct! This example demonstrates that routine application of
LM--applied during the course of the experimental work (or the
publication process) in the later studies (10,11)--would have prevented
uninten ded multiple publications of the same structure, the error in
symmetry determination, and the later effort that corrected the error in
symmetry determination.3. Conclusion--Enhancement of the Publication Process via LM The above examples reveal that a significant problem in the publication process exists and that positive action needs to be taken to prevent unintended multiple publications of the same structure. Fortunately, LM comprises a simple and very powerful method to identify the same or related compounds. Clearly, the key advantage of routine application of LM is that the researcher is oriented o·ri·ent n. 1. Orient The countries of Asia, especially of eastern Asia. 2. a. The luster characteristic of a pearl of high quality. b. A pearl having exceptional luster. 3. with respect to previous work on the same and related structures. Consequently, as an integral part of the experimental and publication process, standard procedure dictates that LM should be routinely applied--especially at two key points of the process. First, by the experimentalist as soon as a unit cell has been determined and second, by the journal editor prior to acceptance of the manuscript manuscript, a handwritten work as distinguished from printing. The oldest manuscripts, those found in Egyptian tombs, were written on papyrus; the earliest dates from c.3500 B.C. for publication. For convenience, this identification procedure can be fully automated au·to·mate v. au·to·mat·ed, au·to·mat·ing, au·to·mates v.tr. 1. To convert to automatic operation: automate a factory. 2. at both these points.
Table 1
Crystallographic parameters reported for piperidinium
dihydrogenphosphate ([C.sub.5] [H.sub.10][NH.sub.2]*[H.sub.2]
[PO.sub.4]) (5,6). Comparison of the reduced cell parameters shows that
the two structures are the same. Numbers in parentheses represent
standard deviations
Literature cells
Piperidinum dihydrogenphosphate
Lattice I Lattice II
Cell Cell 1 Cell 2
a([Angstrom]) 6.2397(6) 8.385(2)
b([Angstrom]) 8.4191(7) 6.227(2)
c([Angstrom]) 8.8523(2) 8.836(4)
a([degrees]) 112.485(4) 90.0
[beta]([degrees]) 89.992(4) 112.43(3)
[gamma]([degrees].sup.3]) 90.104(7) 90.0
V([[Angstrom].sup.3]) 429.68(5) 426.4
System Triclinic (a) Monoclinic
Sp. Gr. P1 [P2.sub.1]
Yr. Pub. 2001 1989
Ref. No. [51] [6]
Reduced cells
Piperidinum dihydrogenphosphate
Lattice I Lattice II
Cell R-Cell 1 R-Cell 2
a([Angstrom]) 6.2397 6.227
b([Angstrom]) 8.4191 8.385
c([Angstrom]) 8.8523 8.836
a([degrees]) 112.485 112.43
[beta]([degrees]) 89.992 90.0
[gamma]([drgrees]) 90.104 90.0
V([[Angstrom].sup.3]) 429.68 426.4
(a) Cell 1 of Lattice I was reported as triclinic. However, the reduced
form No. 35 (7) for Cell 1 shows that the lattice is metrically
monoclinic.
Table 2
Crystallographic parameters reported for orthorhombic N,
N'-diphenylguanidine (8,9). A comparison of the reduced cell parameters
reveals that the two structures are the same. Numbers in parentheses
represent standard deviations
Literature cells
N,N'-diphenylguanidine
Lattice I
Cell Cell 1
a([Angstrom]) 9.003(5)
b([Angstrom]) 12.699(3)
c([Angstrom]) 20.522(8)
[alpha]([degrees]) 90.0
[beta]([degrees]) 90.0
[gamma]([drgrees]) 90.0
V([[Angstrom].sup.3]) 2346.3(17)
System Orthorhombic P
Sp. Gr. [P2.sub.1][2.sub.1][2.sub.1]
Yr. Pub. 1999
Ref. No. [8]
N,N'-diphenylguanidine
Lattice II
Cell Cell 2
a([Angstrom]) 12.653(5)
b([Angstrom]) 20.54(2)
c([Angstrom]) 8.944(5)
[alpha]([degrees]) 90.0
[beta]([degrees]) 90.0
[gamma]([drgrees]) 90.0
V([[Angstrom].sup.3]) 2324(2)
System Orthorhombic P
Sp. Gr. [P2.sub.1][2.sub.1][2.sub.1]
Yr. Pub. 1998
Ref. No. [9]
Reduced cells
N,N'-diphenylguanidine
Lattice I
Cell R-Cell 1
a([Angstrom]) 9.003
b([Angstrom]) 12.699
c([Angstrom]) 20.522
[alpha]([degrees]) 90.0
[beta]([degrees]) 90.0
[gamma]([degrees]) 90.0
V([[Angstrom].sup.3]) 2346.3
N,N'-diphenylguanidine
Lattice II
Cell R-Cell 2
a([Angstrom]) 8.944
b([Angstrom]) 12.653
c([Angstrom]) 20.540
[alpha]([degrees]) 90.0
[beta]([degrees]) 90.0
[gamma]([degrees]) 90.0
V([[Angstrom].sup.3]) 2324.5
Table 3
Crystallographic parameters reported for 1,8-terpin
([C.sub.10][H.sub.20][O.sub.2]* [H.sub.2]O) in references [10-12].
Comparison of the reduced cell parameters reveals that all three
compounds are the same. Numbers in parentheses represent standard
deviations
Literature cells
1,8-Terpin
Lattice I Lattice II Lattice III
Cell Cell 1 Cell 2 Cell 3
a([Angstrom]) 10.930(2) 10.912(3) 18.421
b([Angstrom]) 18.425(5) 22.791(4) 22.791
c([Angstrom]) 22.791 10.705(2) 10.912
[alpha]([degrees]) 90.0 90.0 90.0
[beta]([degrees]) 90.0 120.64 90.0
[gamma]([degrees]) 90.0 90.0 90.0
V([[Angstrom].sup.3]) 4589.8 2290.6 4581.2
System Orthorhombic F Monoclinic C Orthorhombic F
Sp. Gr. Fdd2 Cc Fdd2
Yr. Pub. 1982 1986 1988
Ref. No. [12] [11] [10]
Reduced cells
1,8-Terpin
Lattice I Lattice II Lattice III
Cell R-Cell 1 R-Cell 2 R-Cell 3
a([Angstrom]) 10.712 10.705 10.705
b([Angstrom]) 10.712 10.705 10.705
c([Angstrom]) 12.638 12.634 12.634
[alpha]([degrees]) 102.74 102.71 102.71
[beta]([degrees]) 102.74 102.71 102.71
[gamma]([degrees]) 118.65 118.72 118.72
V([[Angstrom].sup.3]) 1147.4 1145.3 1145.3
Reduced forms
1,8-Terpin
Lattice I Lattice II Lattice III
Form RFI RF2 RF3
a*a 114.75 114.60 114.60
b*b 114.75 114.60 114.60
c*c 159.72 159.62 159.62
b*c -29.87 -29.77 -29.77
a*c -29.87 -29.77 -29.77
a*b -55.00 -55.06 -55.06
Form No. 16 16 16
Acknowledgment acknowledgment, in law, formal declaration or admission by a person who executed an instrument (e.g., a will or a deed) that the instrument is his. The acknowledgment is made before a court, a notary public, or any other authorized person. The author thanks Ronald Munro for his valuable suggestions and insightful comments. Accepted: September 12, 2002 4. References (1.) A. D. Mighell, The Reduced Cell: Its Use in the Identification of Crystalline Materials, J. Appl. Cryst. 9, 491-498 (1976). (2.) V. L. Karen (Himes) and A. D. Mighell, NBS (National Bureau of Standards) See NIST. NBS - National Bureau of Standards: part of the US Department of Commerce, now NIST. *LATTICE: A Program to Analyze Lattice Relationships, Natl. Bur. Stand. (U.S.) Tech. Note 1214 (1985). (3.) A. D. Mighell and V. L. Karen, Compound Identification and Characterization Using Lattice-Formula Matching Techniques, Acta Cryst. A42, 101-105 (1986). (4.) S. K. Bryam, C. F. Campana, J. Fait, and R. A. Sparks, Using NIST (National Institute of Standards & Technology, Washington, DC, www.nist.gov) The standards-defining agency of the U.S. government, formerly the National Bureau of Standards. It is one of three agencies that fall under the Technology Administration (www.technology. Crystal Data within Siemens' Software for Four-Circle and Smart CCD CCD in full charge-coupled device Semiconductor device in which the individual semiconductor components are connected so that the electrical charge at the output of one device provides the input to the next device. Diffractometers, J. Res. Natl. Inst. Stand. Technol. 101, 295 (1996). (5.) K. Kaabi, C. Ben Nasr, and M. Rzaigui, Synthesis and Crystal Structure of [C.sub.5][H.sub.12][NPO NPO [L.] nil per os (nothing by mouth). NPO abbr. Latin nil per os (nothing by mouth) NPO Nothing by mouth .sub.4][H.sub.2], J. Solid State Chem. 161, 307-311 (2001). (6.) C. B. Aakeroy, P. B. Hitchcock, B. D. Moyle, and K. R. Seddon, A Novel Class of Salts for Second Harmonic Generation Second harmonic generation (SHG; also called frequency doubling) is a nonlinear optical process, in which photons interacting with a nonlinear material are effectively "combined" to form new photons with twice the energy, and therefore twice the frequency and half the , J. Chem. Soc., Chem. Commun. (23) 1856-1859 (1989). (7.) A. D. Mighell, Lattice Symmetry and Identification--The Fundamental Role of Reduced Cells in Materials Characterization, J. Res. Nail. Inst. Stand. Technol. 106, 983-995 (2001). (8.) J. A. Paixao, A. Matos Beja, P. S. Pereira Silva sil·va also syl·va n. pl. sil·vas or sil·vae 1. The trees or forests of a region. 2. A written work on the trees or forests of a region. , M. Ramos Silva, and L. Alte Da Veiga, A new orthorhombic phase of N,N'-diphenylguanidine, Acta Cryst. C55, 1037-1040 (1999). (9.) A. Tanatani, K. Yamaguchi, I. Azumaya, R. Fukutomi, K. Shudo, and H. Kagechika, N-Methylated Diphenylguanidines: Conformations, Propeller-Type Molecular Chirality chirality (kī·ralˑ·i·tē), n the “handedness” property of organic compounds (containing an asymmetrical carbon) that gives rise to structures that , and Construction of Water-Soluble Oligomers with Multilayered mul·ti·lay·ered adj. Consisting of or involving several individual layers or levels. Aromatic aromatic /ar·o·mat·ic/ (ar?o-mat´ik) 1. having a spicy odor. 2. in chemistry, denoting a compound containing a ring system stabilized by a closed circle of conjugated double bonds or nonbonding electron pairs, e.g. Structures, J. Am. Chem. Soc. 120, 6433-6442 (1998). (10.) R. E. Marsh and F. H. Herbstein, More Space-Group Changes, Acta Cryst. B44, 77-88 (1988). (11.) T.-I. Ho, M.-C. Cheng, S.-M. Peng, F.-C. Chen, and C.-C. Tsau, Structure of Terpin, Acta Cryst. C42, 1787-1789 (1986). (12.) T. Suga, T. Hirata, and T. Aoki, An X-ray Crystallographic Study on cis-trans Configurational Assignment to "cis-" and "trans-1, 8-terpias" and a Proposal of New Designation for Discriminating dis·crim·i·nat·ing adj. 1. a. Able to recognize or draw fine distinctions; perceptive. b. Showing careful judgment or fine taste: between the Configurational Isomers isomers (ī´sōmurz), n.pl 1. organic compounds having the same empirical formula–i.e. , Bull. Chem. Soc. Jpn. 55, 914-917 (1982). About the author: Alan D. Mighell has been a research scientist at NIST since 1964. His research interests include structural crystallography and the design and development of mathematical procedures for materials identification, for establishing lattice relationships, and for the evaluation of crystallographic data. The National Institute of Standards and Technology National Institute of Standards and Technology, governmental agency within the U.S. Dept. of Commerce with the mission of "working with industry to develop and apply technology, measurements, and standards" in the national interest. is an agency of the Technology Administration, U.S. Department of Commerce. |
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