Input Atom (Site)
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Dialog Box: Input Atom (Site) [ Control Window ]

Label. Each atom may be assigned a label of up to 6 characters. Labels in CRYSCON may not contain any embedded blanks. Any embedded blanks or leading blanks in labels in import files will be converted to underscores. Trailing blanks will be stripped.

Fractional coordinates. For crystals, the x , y and z coordinates should be in fractions of the unit cell.

Type. It is usually expedient to enter the same type for all atoms which are bonded similarly (e.g. all carbons, all silicons, all six-coordinated cations, all oxygens, etc.) to save effort in defining bonds and polyhedra. The atomic number can usually be used for the type, although there are situations in which different type numbers should be used for the same element.

In a transformation, if atoms are found to be superimposed the type and other parameters are simply taken from the initial atom generated in this position. Thus if it is known that atoms are going to be consolidated, for example in a super- to sub-cell transformation, it may be a good idea to use a single type for those which will be consolidated.

Any change in the Label or Type for the site will be transmitted to the first site occupant.

The list box gives the current occupants of the site. To modify individual occupants, double click on the selection or click the Revise button.

In the Temperature Factor group, the type number as used in ORTEP must be specified. The temperature factors are given below (in abbreviated form). The common type numbers are given in the dialog; other types are rarely used nowadays. Supply the b, B or U double-subscripted coefficients as required - in type 0, the b coefficients are usually called betas. If the type is isotropic, the single value (B or U) is given in the (11) box.

ORTEP Types of Temperature Factors

Type 0 - e^(-b11h^2...+2b12hk...) *** Beta aniso

Type 1 - e^(-b11h^2...+b12hk...)

Type 2 - 2^(-b11h^2...+2b12hk...)

Type 3 - 2^(-b11h^2...+b12hk...)

Type 4 - e^(-.25(a*^2B11h^2...+2a*b*B12hk...)) *** B aniso

Type 5 - e^(-.25(a*^2B11h^2...+a*b*B12hk...))

Type 6 - ISOTROPIC - e^(-B(sin(theta)/lambda)^2) *** B iso

Type 7 - sphere of arbitrary radius

Type 8 - e^(-2pi^2(a*^2U11h^2...+2a*b*U12hk...)) *** U aniso

Type 9 - e^(-2pi^2(a*^2U11h^2...+a*b*U12hk...))

Type 10 - ISOTROPIC - e^(-2pi^2U(sin(theta)/lambda)^2) *** U iso (not a standard ORTEP type)