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Inorganic Chemistry Division (II)
Chemical Nomenclature and Structure Representation Division (VIII)


Number: 2003-034-1-200

Title: Classification, terminology and nomenclature of borophosphates

Task Group
Rüdiger Kniep

Members: Andre Durif, Erwin Parthe, S. Sevov, and Jing-Tai Zhao

Completion Date: 2008 - project completed

Throughout the literature a variety of systems for the nomenclature of borates are used. On the other hand in recent years numerous compounds were obtained containing boron and phosphorus, which are called borophosphates. These are built with B-O-B or B-O-P linkages where structural information and formula are available. Depending on the formula and structure of the compound, it is observed that different nomenclatures are used by different people or naming of the compound is ignored. There are several examples in recent literature where some difficulties arise in naming borophosphates. The objective of this project is to provide terminology, classification and naming of novel borophosphate compounds depending on structure and linking principles.

Borophosphates are the intermediate compounds of the MxOy.B2O3.P2O5 (H2O) system which contain complex anionic structures built of BO4, BO3 and PO4 groups and their partially protonated species. Numerous borophosphate compounds have been synthesized by solid state, solution, hydrothermal and microwave techniques. The structure of these is based on the linking principles of the primary building units which should be classified. Borophosphate anions extend from isolated species, rings, chains, oligomers, layers and frameworks like silicates.

The main goal of this project is classified as:
1. To investigate some specific structures of boron compounds, containing phosphates, that have close relation to silicates. Boron in nature usually occurs as oxy compounds. In borates the structures are determined by O:B ratio and number of oxygen atoms shared by each BO3 group. In most of the compounds boron is three coordinated, but there are others where there is a tetrahedral coordination or mixed coordination. The presence of P in the structural units complicates the structures. On the other hand there are many hydroxyborates where OH is bonded to boron as the part of 3 or 4 coordination group. Searching the literature for different structural units of borophosphates, may lead to the revision of some formula, their classification and assigning names to them.

2. The publication of such classification and nomenclature would enlighten and stimulate the researchers to synthesize new borophosphates. On the other hand micro- and mesoporous properties of some of these compounds are very important from the point of designing zeolite like structures or catalysts.

June 2007 - The task group will meet on 6-7 August 2007 in China to review the latest progress and formulate a report based on a recent review by Bastian Ewald, Ya-Xi Huang, and Rüdiger Kniep titled "Structural Chemistry of Borophosphates, Metalloborophosphates, and Related Compounds", Z. Anorg. Allg. Chem. 2007, 633, 1517-1540 [doi: 10.1002/zaac.200700232]

August 2008 - During subsequent discussions, the Task Group concluded that since the borophosphates are a very diverse group of compounds with complex structures that span 0-3 dimensional in nature and with a variety of compositions, that it would be extremely difficult to propose a systematic nomenclature covering all possibilities. The Task Force therefore regards its project as complete.

Last update: 16 September 2008


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Page last modified 16 September 2008.
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