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Preparation of Rare Earth Group VA Compounds with Th(3)P(4) Structure

IP.com Disclosure Number: IPCOM000095059D
Original Publication Date: 1965-Sep-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Gambino, RJ: AUTHOR

Abstract

This method is for preparing compounds of rare-earth metals with antimony or bismuth. These compounds have the anti-Th(3)P(4) crystal structure with chemical formulae of the type A(4)B(3). A is the rare earth metal and B is antimony or bismuth. Several compounds of this group are ferromagnetic such as Gd(4)Bi(3), Gd(4)Sb(3) and Dy(4)Sb(3). These compounds have Curie temperatures of 340 degrees K, 260 degrees K, and 21 degrees K, respectively. The method of preparation of these compounds consists of the following steps.

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Preparation of Rare Earth Group VA Compounds with Th(3)P(4) Structure

This method is for preparing compounds of rare-earth metals with antimony or bismuth. These compounds have the anti-Th(3)P(4) crystal structure with chemical formulae of the type A(4)B(3). A is the rare earth metal and B is antimony or bismuth. Several compounds of this group are ferromagnetic such as Gd(4)Bi(3), Gd(4)Sb(3) and Dy(4)Sb(3). These compounds have Curie temperatures of 340 degrees K, 260 degrees K, and 21 degrees K, respectively. The method of preparation of these compounds consists of the following steps.

The rare-earth metal is premelted to reduce its surface area in order to moderate its subsequent reaction with antimony or bismuth. The solid rare-earth metal is then reacted with molten antimony or bismuth to form an intermediate product with the rock salt structure and a 1:1 stoichiometry. Finally, the intermediate product, in powder form, is reacted with the required amount of rare- earth metal to give the 4:3 stoichiometry at a temperature below the incongruent melting point of the compound but above the melting point of the rare-earth metal.

In the preparation of Gd(4)Bi(3), for example, a given amount of gadolinium metal is melted in a tantalum crucible in vacuum. The weight of gadolinium is selected so that after melting it occupies about half the volume of the crucible. The required weight of bismuth powder for the GdBi stoichiometry is placed over the solidified gadolini...