Notes about Authors

The Bulletin of Entomological Research publishes original research papers, review articles and short communications concerning insects, mites, ticks or other arthropods of economic importance in agriculture, forestry, stored products, biological control, medicine, animal health and natural resource management. The geographical scope of the Bulletin is worldwide. Taxonomic papers are accepted if relevant. The Bulletin is also produced electronically and is available on the WWW to subscribers. The Bulletin also publishes a supplement series.


Author checking of manuscripts
All papers must be submitted in Crystallographic Information File (CIF) ASCII format (MIME or other encoded formats should be avoided if possible). Authors are required to pre-check their submission by e-mailing their CIF to cheekeif@iucr.org. A check report will be returned automatically to the sender's e-mail address. Any reported problems with the submitted data will need to be corrected before submission. If the report contains validation alerts about the consistency, adequacy or quality of the data, these will need to be addressed, or, if the authors consider there are specific reasons for these alerts, the validation response form (VRF) supplied by eheekeif can be completed and included in the submitted CIF.
The text and tables of a paper, as distributed to the Coeditors and referees, may be previewed by sending the CIF (after t These notes are also available from http://www.iucr.org/ actac. completing the pre-check) to printcif@iucr.org. A PostScript file of the paper will be returned for local printing. Note that use of these automatic facilities does not constitute a submission to Section C. The checkcif and printcif facilities are also accessible via the web address http: //www. iucr.org/actac.

Categories of submission
Section C publishes three categories of papers. The requested category must be specified in the submitted CIF as _publ_requested_category, using one of the codes listed below.
(a) Full papers describe one or more structure determinations. These submissions are validated (see §3) and peer reviewed. The accepted paper is printed in the journal and the CIF is accessible from the Section C web address http://www.iucr.org/actac.
The category codes used to identify these papers are FI for inorganic, FM for metal-organic, and FO for organic structures.
(b) CIF-access papers describe one or more structure determinations. The submitted CIF is validated identically to (a) but the text is not peer reviewed. The title, authors, synopsis and scheme of the paper will appear in the Table of Contents of the journal and the CIF is accessible from the address http://www.iucr.org/actac. The category codes used to identify these papers are c I for inorganic, CM for metal-organic, and co for organic structures.
(c) Addenda and Errata are short printed papers describing additions to, comments on, or errata to existing Section C publications and are not intended for interim reports of work in progress. The text should not exceed 1000 words. Addenda and Errata are peer reviewed. The category code for these papers is AD.

Method of submission
CIFs for full papers should be sent to the e-mail address eifpub@iuer.org, whereas cif-access submissions should be sent to cifaecess@iucr.org. All submitted CIFs must have been prechecked using the facilities described in §1.1.
Authors are requested not to send the additional material required for submission until the CIF validation checks summarized in §3 have been carried out and they have received formal acknowledgement of the submission. At that time the Transfer of Copyright Agreement form (Appendix 6) should be sent to sions), should be sent by ftp (Appendix 2). Note that structure factors should always be supplied in a separate file.

Languages of submission
The languages of publication are English, French, German and Russian.

Author's warranty
The submission of a paper is taken as an implicit guarantee that the work is original, that it is the author(s) own work, that all authors concur with and are aware of the submission, that all workers involved in the study are listed as authors or given proper credit in the acknowledgements, that the results have not already been published (in any language or medium) or deposited in a public access database, and that the paper is not being considered and will not be offered elsewhere while under consideration for an IUCr journal. For these reasons, the submission must be made over the signature of at least one author.

Copyright
Except as required otherwise by national laws, the author must sign and submit a copy of the Transfer of Copyright Agreement form (Appendix 6) for each manuscript before it can be accepted.

Handling of manuscripts
Each submitted CIF is checked in Chester for completeness and data integrity. If incomplete or inadequate it will be returned to the author for correction. The data-validation criteria applied in these checks are summarized in §3, and more detailed information is available from the web site http:// www. iucr. org/actac. Papers failing to meet these criteria are handled differently according to whether a completed validation response form (VRF) giving reasons for the failure has been included in the CIF. If a VRF is present, the CIF and check report is e-mailed to a special Co-editor who will assess the validity of the explanation. If a VRF is not present in a failed CIF, the submission will be returned to the contact author. Papers accepted for publication will be assigned an IUCr data-validation number (e.g. IUC9800856). This will be published in the journal to allow retrieval of the CIF from the IUCr archives.
For CIF-access papers the title, authors, synopsis and scheme for molecular compounds will normally appear in the journal within two months of data validation. Full papers will be forwarded, together with the Check Report, to a Co-editor, who is responsible for the review steps and future communications with the authors up to the acceptance stage. Failure to respond to a communication from either a Co-editor or the Chester editorial staff within three months will result in the automatic withdrawal of the paper. If major revisions are made to the submission the journal reserves the right to reset the date of receipt of the paper to the date of re-submission. Any amendments to a paper during its review must be indicated on the printed manuscript provided, as this document is used by the editorial staff to update and revise the archived CIF.
Once a paper is accepted, it is the responsibility of the Managing Editor to prepare the paper for printing and to correspond with the authors and/or the Co-editor to resolve publication ambiguities or inadequacies. The date of acceptance that will appear on the published paper will be the date on which the Managing Editor receives the last item needed.

Status of a submission
Authors may obtain information about the current status of a paper either from the web site http: //www. iucr. org/iucrtop/journals/status, html or by sending an e-mail, containing the reference code of the paper and the author's name as the subject line (e.g. JA1325 Smith), to the address status@iucr.org.

Reprints
Twenty-five reprints of each printed article will be provided to the contact author free of charge.

Author grievance procedure
An author who believes that a paper has been unjustifiably treated by the Co-editor may appeal initially to the Section Editor, and then to the FAitor-in-Chief if still aggrieved by the decision.

Submission of related structures
Authors studying a series of closely related structures are encouraged to submit these for publication as a single paper. The CIF approach is well suited to multi-structure submissions. The journal reserves the right to require that a series of single structure papers on closely related materials be merged.

Publication requirements
The publication requirements for the text, tabular and graphical material are described in this section. The standards for numerical and codified data are summarized in §3, and a list of all items required for submission is given in Appendix 3. Each item described in this section is re,£1uired for a full paper submission. Only the items described in § §2.1, 2.2, 2.4, 2.5, 2.6, 2.7, 2.9, 2.11 and :2.13 are required for a CIF-access submission. Crystal diagrams should not be supplied for ia CIF-access submission.

Title and authors
The Title should be short and informative. Avoid complicated IUPAC names and redundant phrases such as 'Crystal Structure of ...'. However, if the paper describes special techniques, such as powder, neutron or synchrotron diffraction studies for example, this should be alluded to in the title. The full first name of each author is preferred. The e-mail address of the contact author should be included in the CIF using the data item _publ_contact_author_email. Note that data items _publ_section_title_footnote and __.publ_author_footnote are for inserting footnotes to the title and to individual authors.

Abstract
The Abstract must be written in English and should summarize only the most important aspects of the study. It should be capable of being understood on its own without access to the text or figures. It should not contain the crystal data. The systematic IUPAC name and the chemical formula should be given here, if they are not included in the Title.

Comment
The Comment is the descriptive section of a full-paper submission. It is expected to be an informative but concise discussion of the novel aspects of the study, and include the following key aspects: (a) The reasons for the study.
(b) The origin of the material studied, including background material and references to related structural studies. [Note that details of the chemical extraction, synthesis and crystallization processes should be given in the Experimental section (see §2.4 Note that if a study warrants little discussion, the submission may be better suited to publication as a CIF-access paper, and authors may be advised of this during the review process.

Experimental data
Experimental data (see Appendix 3) are tabulated under the sub-headings Crystal data, Data collection and Refinement. The descriptive text item _publ_sec t ion_expt lprep should give sufficient information on the chemical and crystal preparation, and identification (e.g. on melting points and densities), to reproduce the experiment. Additional measurements (e.g. NMR spectra) supporting the crystallographic study may also be included. The item _loubl_section_exptl_refinement details special aspects of the data collection, space-group identification, data processing, structure determination, refinement and hydrogenatom treatment.

Acknowledgements
Acknowledgement should be given for any assistance provided to the study (see §1.5).

References
References to published work must be cited in the format detailed in §6. If reference is made to unpublished work, prior consent must be first obtained from the authors of that work.

Atomic sites
Except for structures involving special site symmetries, atom coordinate and displacement parameters will not be printed.
These are available to readers in CIF format from the web site http : / / www. iucr. org/actac. The _a tom_s i re_ coordinate and displacement parameters must be supplied with standard uncertainty values (see §5.1). The parameter constraints and restraints applied to the refinement process, and the anisotropic atomic displacement parameters (as /f J), must also be supplied.
If atomic displacement parameters other than U or U 'j are used, the exact form of the displacement-factor expression should be indicated in _publ_section_exptl_refinement.

Selected geometrical data
Interatomic bond lengths, intermolecular non-bonded contact distances, bond angles and torsion angles should be supplied, but only values that are novel should be flagged for printing by setting the _geom .... f lag value to yes. The data to be printed will be reviewed by the Co-editor. All submitted geometry data are available to readers in CIF format from the web site ht tp : / / ww-w. iucr. org/actac.

Chemical scheme
A chemical structural diagram (a typical example is shown below) must be included for molecular compounds.

Crystallographic diagram
Only one crystallographic diagram is usually permitted for each structure presented in the paper. Diagram requirements are given in §4. A displacement ellipsoid diagram is required either for publication or to be used in the review process.

Contents and Synopses
The Table of Contents of the joumal will list the title and author(s) of all papers. For full papers, each entry will be accompanied by either a chemical structural diagram (see §2.9) for molecular compounds or a written synopsis for compounds that cannot be shown as a chemical structural diagram. For CIFaccess papers, all Table of Contents entries will include a written synopsis; for molecular compounds this will be accompanied by a chemical structural diagram. The synopsis should be one or two sentences (less than 40 words) in length and should be given in _publ_sec t ion_synops i s.

Powder diffraction data
A CIF powder template and list of data items for inclusion in a powder diffraction paper are available by ftp (files /pub/rietform.cif and /pub/rietreq. ist, respectively) and notes on submission of powder papers are available on request from the Editorial Office. The numerical intensity of each measured point on the profile (as a function of scattering angle) will be deposited with the IUCr and, in the case of X-ray diffraction data, sent by the Co-editor to the International Centre for Diffraction Data (ICDD), 12 Campus Boulevard, Newtown Square, PA 19073-3273, USA. These data will be checked and assigned an ICDD reference number which will, where possible, be published in the paper. Papers reporting Rietveld refinements should include a figure showing the diffraction profile and the difference between the measured and calculated profiles.

Structure factors
The reflection data h, k, l, Ym .... or Ym .... Ycalc (where Y is I, F 2, or F), should be supplied as an electronic file in CIF format. Authors should indicate if the Y values are corrected for absorption and extinction effects in this file and in the __pub l_sec t i on_exp t ] _re f i nemen t section of the paper.

Data standards
A list of all data required for submission is given in Appendix 3. If the submitted data are incomplete, inadequate or incorrect the author will be informed promptly. Authors are required to pre-check each CIF (see §1.1) prior to submission. A more complete description of the data-validation checks applied to submitted CIFs is available from the web site http: //www. iucr.org/actac.
The most important data requirements are summarized below.

_chemical_formula_moiety _chemical_formula_sum
The chemical formula must be consistent with the atomic content specified by the _atom_site_ information, and match the _chemical_formula_weight (see Appendix 3).

_symme t ry_space_group_name_H-M
The space group must encompass the highest symmetry permitted by the diffraction intensities, and be consistent with the _cel l_length_ and _eel l_angle_ values (see Appendix 3). _cell_formula_units_Z The number of formula units in the unit cell must comply with that expected from the chemical formula, the space group and the _atom_site_ data.

_expt l_c rys t al_colour
The crystal colour should comply with the codes listed in A type code must be accompanied by a reference to the method or the software used; this should be given in the field _expt l_absorpt_process_detai is. The need for absorption corrections, and the appropriate type of correction, is dependent on the it value _exptl_absorpt_coefficient_mu and the crystal size values _exptl_crystal_size_min, _mid and _max. If x is the medial size _mid, the product tlx provides a gauge to the type of correction needed. Analytical or numerical corrections are strongly recommended if t~x exceeds 1.0 and mandatory if I~x is above 3.0. If I~x is below 0.1 corrections are usually unnecessary, otherwise t,-scan or empirical methods are acceptable. Refined absorption methods are discouraged except in special circumstances. The transmission-factor limits _expt l_absorpt_correc t ion T min and _max should agree with those expected for the crystal shape and size, and/~.

_re f ins_number_total
The number of symmetry-independent reflections excludes the systematically extinct intensities. Authors are encouraged to use all of these reflections in the refinement of the structure parameters.

_re f ins_threshold_expression
This is identical to the item _ref ins_observed _criterion. This threshold, which is based on multiples of crl, crF 2 or crF, serves to identify the significantly intense reflections, the number of which is given by _ref lns_number_gt. These reflections are used in the calculation of _refine is R factor_gt. The multiplier in the threshold expression should be as small as possible.
The 8max of measured reflections should be such that sin(gmax/A exceeds 0.6/1 -I (i.e. 0max>25 ° for MoKa; 8max > 67 ° for Cu Ka). It is assumed that all unique reflections out to the specified 0max are measured. This provides the minimum number of reflections recommended for an average structural study. If intensities are consistently weak at the recommended 8m~x, low-temperature measurements may be needed unless a study at a specific temperature (or pressure) is being reported. _di f f rn_measured_f rac t ion_theta max This is intended for area-detector data, but is also useful as a general measure of data completeness. It is the fraction of unique (symmetry-independent) reflections measured out to _di f frn_reflns_theta_max. Ideally, this should be as close to 1.0 as possible.
_di f f rn_re f ins_thet a_ ful 1 This is intended for area-detector data. 8fu, is the diffractometer angle at which the measured reflection count is close to complete. The fraction of unique reflections measured out to this angle is given by _di f f rn_measured_f ract ion_theta_ful i. Alternatively, a breakdown of data completeness and merging statistics as a function of O may be requested if deemed necessary.
_diffrn_reflns av R_equivalents Sufficient symmetry-equivalent reflections must be measured to provide a good estimate of the intensity repeatability. This is particularly important when absorption corrections are applied (this value is calculated after the corrections are applied to the intensities).

refine is R factor_gt
This is identical to the item _refine is R factor_obs and is calculated for the number of reflections _ref lns_number_g t. Note that this value is not intended as a reliable gauge of structure precision; this is better determined from the standard uncertainties of the parameters (which depend on the number and the reliability of the measured structure factors used in the refinement process).

_refine Is number_reflns
The number of reflections used in the refinement should be as large as possible, and is expected to be greater than the number of refined parameters _refine is number_parameters by at least a factor of 10 if the structure is centrosymmetric, or by a factor of 8 if it is not. If the number of refinement reflections is set equal to _reflns_number_gt, then the o-multiplier in _ref ins_threshold_expression should be kept as small as possible.

_refine is number parameters
This is the number of coordinate, atomic displacement, scale, occupancy, constraint and restraint parameters refined independently in the least-squares process. It is possible, and sometimes desirable, to reduce that number by the appropriate application of geometric constraints. Authors should note that the method by which the H-atom parameters are determined dictates how the hydrogen-bond geometry may be considered in the paper. In particular, H-atom sites which have been fixed or constrained by geometry will have unknown s.u. values, and this uncertainty must be reflected in conclusions drawn in the discussion.

_refine is weighting_scheme
Refinements based on unit weights are not acceptable.

_refine is shift/su_max
This is identical to the item _refine ls shift/esd_max. It is the largest ratio of the refinement shift to standard uncertainty and typically is within _+0.01 if sufficient leastsquares refinement cycles have been employed. A value above _+0.05 is considered unusual and values beyond _+0.1 are a signal of incomplete refinement, unaccounted-for disorder or high correlation between parameters that should be constrained. Authors should explain the reasons for a high value in All geometry values must originate from the submitted _atom_site_fract_ values. Only novel geometry values of significance to the structure will be printed. These must be identified with a _geom .... flag value of yes in the submitted CIF; all other geometry values must be flagged with a no.

_atom_site_
Atomic coordinates for molecular structures should be supplied as connected sets. atom_site_occupancy values should be 1.0 except for disordered or non-stoichiometric atom sites. Atom sites constrained to model disorder must be indicated by _atom_si re_disorder_group. The overall packing in the structure will be checked for significant vacant regions (i.e. voids) indicating omitted solvent molecules. Note that s.u. values should not be appended to parameters which are fixed by symmetry, geometry or other constraints.
_atom_site_aniso U Checks will be made for non-positive-definite anisotropic atomic displacement parameters. The ratio of maximum to minimum eigenvalues should not, except in special circumstances (e.g. disorder), exceed 5.
_refine Is abs_structure_details This item should describe the method applied, and the number of Friedel-related reflections used, in the measurement of the absolute structure parameter (e.g. _refine is abs_structure_Flack). If the structure is noncentrosymmetric, and atoms heavier than Si are present, an absolute structure parameter is expected. The reliability of this parameter increases with the number of Friedel-related intensifies, and a complete set of Friedel pairs is strongly recommended.

Publication
Diagrams are only required for full papers. Normally only one diagram will be published per structure. For papers reporting molecular structures this should be a molecular diagram; otherwise it should be a packing or polyhedron diagram. Unique atom sites should be identified with labels consistent with those for the supplied atom coordinates. Distances and angles should not be shown in the crystallographic diagram. A chemical structural diagram must be supplied for molecular compounds (see §2.9 for a typical example).

Submission
Authors should not send diagrams with the CIF submission. They will be contacted when the diagram material is required. Electronic submission as PostScript or HPGL files is preferred (see Appendix 2 for details) but high-quality prints may be sent by post or courier (see §1.3).

Quality
It is essential that diagrams be of publication quality. A clear, well presented crystallographic diagram encapsulates the stereochemistry, the geometry, and, if it is a displacement ellipsoid plot, the structural disorder and thermal motion.

Size
Each diagram should be provided separately without reduction. Diagrams will be reduced by the printer to fit an 80 mm column. The orientation and labelling of the diagram should take this into account.

Lettering and symbols
Fine-scale details and lettering must be large enough to be clearly legible (not less than 1.2 mm in height) when the diagram is one column (80 mm) in width. Atom site labels in crystallographic diagrams should match labels used in the atom site lists and text. The labels should not overlap ellipsoids or bonds. Descriptive matter should be placed in the legend. Packing diagrams must show the cell-axis directions (labelled a, b, c) and the cell origin (labelled 0), but should normally exclude H-atom sites.

Numbering and legends
Diagrams and photographs are to be numbered as figures in a single series, normally in the order in which they are referred to in the text. A list of the legends ('figure captions') should be included in _publ_sect ion f igure_capt ions. Legends of ellipsoid plots must state the probability limit used.

Crystallographic nomenclature
Atom sites not related by space-group symmetry should be identified by unique labels composed of a number appended to the IUPAC chemical symbol (e.g. C5, C7 etc.). Label numbers should not be placed in parentheses. Chemical and crystallographic numbering should be in agreement wherever possible. Crystallographically equivalent atoms in different asymmetric units should be identified in diagrams and text with lower-case roman numeral superscripts appended to the original atom labels Authors are encouraged to follow the recommendation of the International Organization for Standardization (ISO) and use the term standard uncertainty, abbreviated s.u., in place of the traditional term estimated standard deviation [see Schwarzenbach et al. (1995). Acta Cryst. A51,565-569]. The standard uncertainty should be expressed as a number in parentheses following the numerical result and should be on the scale of the least significant digits of the result. The s.u. value should be in the range 2-19. Note that s.u. values should not be appended to parameters which are fixed by symmetry, geometry or other constraints.

Nomenclature of chemical compounds
Names of chemical compounds and minerals should conform to the nomenclature rules of the International Union of Pure and Applied Chemistry (IUPAC), the International Union of Biochemistry and Molecular Biology (IUBMB), the International Mineralogical Association and other appropriate bodies. Any accepted trivial or non-systematic name may be retained, but the corresponding systematic (IUPAC) name should also be given. If help on assigning systematic names is sought from advisory sources, authors are requested to indicate the source consulted.

Units
The International System of Units (SI) is used except that the ~ngstr6m (symbol/~,, defined as 10 -I° m) is generally preferred to the nanometre (nm) or picometre (pm) as the appropriate unit of length. Recommended prefixes of decimal multiples should be used rather than '× l0 n'.

References
References to published work must be indicated by giving the authors' names followed immediately by the year of publication, e.g. Neder & Schulz (1999) or (Neder & Schulz, 1999. Where there are three or more authors the reference in the text should be indicated in the form Smith et al. (1989) or (Smith et al., 1989) etc.
In the reference list, entries for journals [abbreviated in the style of Chemical Abstracts (the abbreviations Acta Cryst., J. Appl. Cryst. and J. Synchrotron Rad. are exceptions)], books, multi-author books, computer programs, personal communications and undated documents should be arranged alphabetically and conform with the following style:

APPENDIX 1 Guidelines for editing CIF text
A limited number of special characters (such as Greek letters,

sub-and superscripts, and a few others) may be indicated in
Other special alphabetic characters should be indicated as fol-CIF text for typesetting purposes, using the special codes listed lows: below. Authors are discouraged from trying to impose any panicular style on the submitted text, and codes for italic and boldface \%a a-ring (~i) German "ss" (13) characters have been omitted intentionally.

Greek letters
In general, the corresponding letter of the Latin alphabet, prefixed by a backslash character. The complete set is:
Superscripts and subscripts should be indicated by bracketing relevant characters with circumflex or tilde characters, thus: Note that \\db, \\tb and \\dd.b should always be followed by a space, e.g. ~ is denoted by C\ktb c.

Complete text using TEX
One further mechanism exists to allow the use of a wider range of special symbols. If, in a text field (one surrounded by semicolons), the first two non-blank characters are '%T', the entire contents of that field will be passed unchanged to the TEX formatting program. Hence, any symbols known to the powerful TEX system may be used, and indeed arbitrarily complex text may be typeset. Any macros defined by the author are valid only through the field in which they are defined, however. It should be stressed that the usual CIF special symbols are not valid in such a field, e.g. U~ would have to be denoted by u$_{\rm eq}$.

Transferring large electronic files
File transfer protocol (tip) should be used to transfer large electronic files exceeding 100K bytes to the Editorial Office in Chester. Files need to be deposited in a directory called 'incoming/c' with a filename constructed from the reference code supplied by Chester. Files containing reflection data in CIF format should be identified by the filename extension . hkl. Where more than one structure is reported in the CIF, the names of the files containing the reflection data should be in the form ref. id.hkl where id is the data_ block code for the corresponding structure in the CIF. Files containing diagrams in HPGL, PostScript or encapsulated PostScript format should be given the extensions .hpg, . ps or . eps, respectively. Multiple files for the same submission should be identified by filenames constructed as ref. id.ex[ where id indicates the contents, e.g. xz1087, figi .ps and xz]087, fig2 .ps.
The procedure for transferring files is shown below.
(i) On your workstation enter: ftp ftp. iucr. org (ii) Wait for r,ogin: prompt and enter: anonymous (iii) Wait for Password: prompt and enter: your e-mail address (iv) Wait for ftp> prompt and enter: cd incoming'/c (v) Transfer a file from your account (e.g. b28.cif) as an identifiable name (e.g. zb1032.hkl): put b28.cif zb1032.hkl (vi) Wait for ftp> prompt before sending another file (vii) Finish off the ftp session by entering: bye (viii) Send an e-mail to Chester (checkin@iucr.org) with a list of the files transferred by ftp

APPENDIX 3 Required CIF data items
The detailed description of most required data items is provided in the published CIF Core Dictionary [Hall et al. (1991). Acta Cryst. A47, 655-685] and subsequent revisions available from http://www, iucr. org/ci f/. The dictionary is available free of charge from the IUCr Editorial Office in Chester (see {}1.3 for address).
New names listed below are flagged with (new) and in some cases are followed by old names [in regular type and flagged with (old)] which are accepted but will be discontinued in the future. Authors may also include other data items in the CIF (see the two _publ_manuscript_incl_extra_ entries towards the end of the list) provided their data names are also listed in the _publ_contact_let ter text. Diffractometer make and type Diffractometer make and type (old)

Mode of intensity measurement and scan
Resolution of area detector (pixels mm-l) Code for absorption correction (see Appendix 4) Literature reference for absorption correction [e.g. '(North et al., 1968

Colour codes
The following colour codes should be used with _exptl_crystal_colour.
The code may be constructed from three attributes appearance, intensity and base colour, in that order, of which only the base-colour string is mandatory.
The colour code may be enclosed in quotes (e.g. ':tight blue'), or the attribute strings may be joined by underscore characters (e.g. metallic_gold). Colour codes constructed from two base colours are also allowed (e.g. red-brown).

AbsoL'ption-type codes
The following codes should be used with _expt 1 _absorpt_correction_type.
Note that this data item should contain only the type code. A reference to the computer program used to apply the absorption corrections should be given in _exp t l_absorp t_proces s_de ta i i s.

Structure-factor codes
The following codes should be used with _refine_Is _s tructure_factor_coe f.

F
Structure-factor magnitude v~qd Structure factor squared z ne'_ Net intensity

H-atom treatment codes
The following codes should be used with _refine _is_hydrogen_treatment.
Note that this data item should only contain the type code. Any detailed text about the determination and refinement of H-atom parameters should be placed in _publ_sec t ion_e×pt l_re f inement.

Weighting-scheme codes
The following codes should be used with _refine ls _weighting_scheme. Note that this data item should contain only the type code. The weighting expression should be given in _refine is weighting_details.  O--_pnbl_sect i on_comment : In the course of our work on phosphanido-btidged homo-and hete[onuclear metal-atom cluster compounds (Haupt, Balsaa & Flk'orke, 1988;Haupt, Heinekamp & Flk'orke, 1989;Flk"orke & Haupt, 1993), we isolated the title compound (1)  The sum and moiety formulae should be present, and entered -according to the rules of the C1F Dictionary. Do not indicate sub-or superscripts.
_chemi ca l_formul a i upac is used to express chemical formulae according to IUPAC rules.

The full Hermann-Mauguin space-group symbol should be used, with a space between each separate component of the symbol.
Loop all symmetry equivalent positions for the space group, including any for lattice centring and a centre of symmetry.
Do not include the units of physical quantities -these are included in the definitions for each data name.
Authors are encouraged to measure the crystal density. However, --if the crystal density was not measured, this should be explicitly stated.

All data names (if present at all in the file) must have a correi sponding value -use .9 (without surrounding quotes) if there is no information on the value.
," Fields denoted ' *_spec i a l_de t a i i s ' are not normally printed in the published paper, but may contain information (often generated by the refinement program) important for critical review purposes.
We accept the convention that a single occurrence of _acom_c¥pe_scat_source is taken to refer to all atoms. But a preferable layout lists data for each atom species, e.g.    Copyright to the above article is hereby transferred (except as otherwise required by national laws*) to the International Union of Crystallography, effective if and when the article is accepted for publication in Acta Crystallographica, Journal of Applied Crystallography or Journal of Synchrotron Radiation. In addition to reproduction in conventional printed form your article will be stored electronically. Your assignment of Copyright signifies your agreement to the journal making arrangements to include your paper in document delivery services, CD-ROMs and electronic databases, etc., worldwide. This transfer of copyright also applies to data submitted in machine-readable form. However, the authors reserve the following: (1) All proprietary rights other than copyright, such as patent rights.
(2) The right to use all or part of this article in future works prepared by or on the behalf of the author.
(3) In the case of 'work for hire', the right of the employer to incorporate all or part of this article in future works.
(4) The royalty-free right of the employer to make copies of this article, without further permission, for his or her own use but not for resale. Any identification or notice appearing on the pages to be reproduced must not be deleted. This Transfer of Copyright Agreement must be signed by at least one of the authors (who agrees to inform the others, if any) or, in the case of a 'work made for hire', by the employer.
By signing this form you certify that your contribution is your original work, has not been published before (in any language or medium) and is not being considered for publication elsewhere; that you have obtained permission for and acknowledged the source of any excerpts from other copyright works; and that to the best of your knowledge your paper contains no statements which are libellous, unlawful or in any way actionable.
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