*FORMULA is used to test the complete formula record.

**
CSD Contents**

To use *FORMULA correctly it is essential to have a knowledge of the syntax conventions used for the storage of formulae in the CSD. The most important are :

- within each residue the elements are ordered in the sequence C, H, D, others alphabetically
- one residue formula is separated from the next by ,

- C6 H4 Br1 N1 O2
- C1 H1 D1 Cl2
- C6 H6 O2,C1 H4 N2 O1
- C2 H2 O4,2(H2 O1)
- C9 H12 N2 O5 S1,1.5(H2 O1)
- C29 H38 O11,x(H2 O1)
- 2(C1 H1 O2 1-),Sr1 2+
- (C3 H3 O6 Sc1)n
- (C6 H12 Ce2 O18)n,4n(H2 O1)

**
Graphics QUEST3D Procedure**

Select *FORMULA from the TEXT sub-menu and respond to the standard text prompts.

**
Basic QUEST Procedure**

**
Ex.1**

T1 *FORM C24 H57 B9 N7 P3

This will register hits for entries having the specified formula. However it will also hit formulae such as:

C24 H57 B9 N7 P3 S1 C24 H57 B9 N7 P31 C24 H57 B9 N7 P3,H2 O1etc.

Note that *FORMULA searching is very slow but can be speeded up by also specifying an *ELEMENT test or appropriate SCRE instructions.

**
Ex.2**

** (a)**

T1 *FORM C10 H10 Ni1 QUES T1

T1 *ELEM Ni T2 *FORM C10 H10 Ni1 QUES T1

SCRE 10 T1 *FORM C10 H10 Ni1 QUES T1

(b) and (c) will provide much faster searches than (a).

**
Related Keywords**

*NRESIDUES, *MAXATOMICNO, *ELEMENT, *SUMFORMULA, *RESFORMULA, *RESIDUE

Volume 2 Chapter 11 Text Menu *JRNL.