Apatite and Spodiosite

Abstract

Apatite is a constituent of all rocks.2 Consequently its presence, to some extent, should be expected in every soil, and this expectation has been confirmed by the microscopic examination of a large number of samples of various types from many parts of the United States.s It is slightly soluble and is hydrolyzed by water, the natural apatites yielding an alkaline solution but one also containing phosphoric acid. It has therefore an importance in soil investigations. It is a carrier of an essential plant nutrient and it is often a guide to the genesis of a particular soil. In the investigation4 of the phosphates of lime which is in progress in this laboratory, apatite is being studied, and in this paper attention is directed to some observations which have been made upon this compound and the related substance, spodiosite. Apatite has been reported as made artificially in several ways: by the action of phosphorus trichloride on caustic lime,5 by passing hydrochloric acid over red hot tricalcium phosphate,' by melting tricalcium phosphate in sodium chloride,' and by melting tricalcium or trisodium phosphate in calcium fluoride or a mixture of these salts.8 It has also

Ba2PO4I, Sr2PO4I, and Pb2PO4I – A New Structure Type and Three of Its Representatives

“…In the 20th century other scientists reported the synthesis of several spodiosite‐MF compounds: Ca 2 PO 4 Cl,6 Ba 2 VO 4 Br, Ba 2 PO 4 I, Ba 2 AsO 4 I, Ba 2 VO 4 I,1 Mn 2 PO 4 Cl, Mn 2 PO 4 Br, Co 2 PO 4 Cl, Mg 2 PO 4 Cl, Mg 2 AsO 4 Cl, Ca 2 VO 4 I, Ca 2 AsO 4 I, Sr 2 VO 4 I, Sr 2 AsO 4 I,7 Mn 2 PO 4 F, and Mn 2 PO 4 Cl,8 but did not publish detailed crystallographic information.…”

Synthetic Phase with the Structure of Apatite

“…WEINSHENK [10] also prepared chlorapatite by heating calcium chloride, ammonium phosphate and ammonium chloride at the temperature of 150 to 180°C in a sealed tube. 1 CAMERON AND MCCAUGHEY [11] prepared fluorapatite by dissolving calcium fluoride in fused disodium phosphate and lixiviating 2 the cooled melt. Artificial fluorapatite sometimes exhibits the peculiarity of re-entrant pyramidal ends or phantom crystals.…”

“…10 JAFFE [18] recognized the precipitation by metathesis and the precipitation by hydrolysis. 11 Sometimes are included among high-pressure methods [24].…”