Docs for schema item formula in Chemical Markup Language (CML)

A molecular formula. It is defined by atomArrays each with a list of elementTypes and their counts (or default=1). All other information in the atomArray is ignored. formula are nestable so that aggregates (e.g. hydrates, salts, etc.) can be described. CML does not require that formula information is consistent with (say) crystallographic information; this allows for experimental variance. An alternative briefer representation is also available through the concise. This must include whitespace round all elements and their counts, which must be explicit. 2005-10-16. The semantics are now the following. A formula must have one or both: A concise attribute A single atomArray child, using array format. it must also have a formalCharge attribute if atomArray is used and the charge is non-zero. The concise, formalCharge and atomArrary information must always be consistent and software should throw an error if not. Until now there was no way of holding inline formula other than concise (although JUMBO5.0 is capable of reading them). We now extend formula.xsd to incorporate this through the attribute "inline" which requires the use of the "convention" attribute. The contents of inline are purely textual. It can be used with or without atomArray or concise but there is no guarantee that it can be interpreted as a meaningful chemical formula or that there is consistency. In some cases a document supplies several formula representations (e.g. the IUCr's CIF). In this case a molecule (or crystal) element might contain several formula children. The semantics of which to use are application dependent.

<xsd:element name="formula" id="el.formula"> <xsd:annotation> <xsd:documentation> <h:div class="summary" xmlns:h="http://www.w3.org/1999/xhtml">A molecular formula.</h:div> <h:div class="description" xmlns:h="http://www.w3.org/1999/xhtml"> <h:p>It is defined by <h:tt>atomArray</h:tt>s each with a list of elementTypes and their counts (or default=1). All other information in the <h:tt>atomArray</h:tt> is ignored. <h:tt>formula</h:tt> are nestable so that aggregates (e.g. hydrates, salts, etc.) can be described. CML does not require that formula information is consistent with (say) crystallographic information; this allows for experimental variance.</h:p> <h:p>An alternative briefer representation is also available through the <h:tt>concise</h:tt>. This must include whitespace round all elements and their counts, which must be explicit. </h:p> <h:p>2005-10-16. The semantics are now the following. A formula must have one or both: <h:ul><h:li>A concise attribute </h:li>A single atomArray child, using array format. </h:ul> it must also have a formalCharge attribute if atomArray is used and the charge is non-zero. </h:p> <h:p> The concise, formalCharge and atomArrary information must always be consistent and software should throw an error if not. </h:p> <h:p> Until now there was no way of holding inline formula other than concise (although JUMBO5.0 is capable of reading them). We now extend formula.xsd to incorporate this through the attribute "inline" which requires the use of the "convention" attribute. The contents of inline are purely textual. It can be used with or without atomArray or concise but there is no guarantee that it can be interpreted as a meaningful chemical formula or that there is consistency. In some cases a document supplies several formula representations (e.g. the IUCr's CIF). In this case a molecule (or crystal) element might contain several formula children. The semantics of which to use are application dependent. </h:p> </h:div> <h:div class="example" href="formula1.xml" xmlns:h="http://www.w3.org/1999/xhtml" /> </xsd:documentation> </xsd:annotation> <xsd:complexType> <xsd:choice> <xsd:choice minOccurs="0" maxOccurs="unbounded"> <xsd:element ref="formula" /> <xsd:element ref="atomArray" /> </xsd:choice> </xsd:choice> <xsd:attributeGroup ref="title" /> <xsd:attributeGroup ref="id" /> <xsd:attributeGroup ref="convention" /> <xsd:attributeGroup ref="dictRef" /> <xsd:attributeGroup ref="count"> <xsd:annotation> <xsd:documentation> <h:div class="specific" xmlns:h="http://www.w3.org/1999/xhtml">Allows for fractional components.</h:div> </xsd:documentation> </xsd:annotation> </xsd:attributeGroup> <xsd:attributeGroup ref="formalCharge"> <xsd:annotation> <xsd:documentation> <h:div class="specific" xmlns:h="http://www.w3.org/1999/xhtml">The charge on the formula. Mandatory if non-zero (i.e. cannot rely on concise)</h:div> </xsd:documentation> </xsd:annotation> </xsd:attributeGroup> <xsd:attributeGroup ref="concise" /> <xsd:attributeGroup ref="inline"> <xsd:annotation> <xsd:documentation> <h:div class="specific" xmlns:h="http://www.w3.org/1999/xhtml">An inline representation of the formula. There are no controlled semantics and it need not be compatible with concise or atomArray.</h:div> </xsd:documentation> </xsd:annotation> </xsd:attributeGroup> </xsd:complexType> </xsd:element>

Definition Type:	Element
Name:	formula
Namespace:	http://www.xml-cml.org/schema
Containing Schema:	schema.xsd
Abstract
Documentation:	A molecular formula. It is defined by atomArrays each with a list of elementTypes and their counts (or default=1). All other information in the atomArray is ignored. formula are nestable so that aggregates (e.g. hydrates, salts, etc.) can be described. CML does not require that formula information is consistent with (say) crystallographic information; this allows for experimental variance. An alternative briefer representation is also available through the concise. This must include whitespace round all elements and their counts, which must be explicit. 2005-10-16. The semantics are now the following. A formula must have one or both: A concise attribute A single atomArray child, using array format. it must also have a formalCharge attribute if atomArray is used and the charge is non-zero. The concise, formalCharge and atomArrary information must always be consistent and software should throw an error if not. Until now there was no way of holding inline formula other than concise (although JUMBO5.0 is capable of reading them). We now extend formula.xsd to incorporate this through the attribute "inline" which requires the use of the "convention" attribute. The contents of inline are purely textual. It can be used with or without atomArray or concise but there is no guarantee that it can be interpreted as a meaningful chemical formula or that there is consistency. In some cases a document supplies several formula representations (e.g. the IUCr's CIF). In this case a molecule (or crystal) element might contain several formula children. The semantics of which to use are application dependent.