X-ray diffraction patterns. Since this temperature is low enough to avoid 

 serious thermal decomposition or structural alteration of wood an effort 

 was made to form the compound directly in ivood. Southern yellow pine blocks 

 were impregnated v/ith lO/o ferric chloride, treated with am.:onia and heat 

 treated in an autoclave for a period of six hours. Tlie wood became dark 

 brovm, presumably because of the formation of iron resinate. These blocks 

 are now bein?? studied for marine borer resistance. Currently no method is 

 available for confirming the presence of the oxide normally obtained by 

 this method. 



p-ferric oxi'-'e monohydrate (,<:^-FeOOH) 



//hen ferric chloride solutions are heated to 80-100°C. an orange-yellow 

 substance precipitates from solutions, '.rhich is considered, generally, 

 to be an allotropic form of fez'ric oxide monohydrate and designated as 

 .he/'^-form. This s"me material sometimes forms gradually in ferric chloride 

 soluti ins when permitted to stand for long periods of time. X-ray dif- 

 fraction patterns show that this substance has a crystalline structure which 

 is distinctly differi3nt from the other oxides. Some question still exists 

 regarding its true structur'', since it alvirays contains a large amount of 

 chloride that may be leached out extensively i/ithout detectible change in 

 X-ray diffraction attern. ..hen the .<v_f orm is dehydrated by heat treat- 

 ment, it changes to the anhydrous );_-form virithout any knovm intermediate. 



An attempt v;as made to treat blocks in such manner as would cause the 

 formation of this oxide in v,-ood. Blocks vrere impregnated with a 10^^ ferric 

 chloride solution by means of the vacuum-pressure method and subsequently 

 heated to 80oC, for several hours while irraaerscd in the same solution. The 

 ferric chloride did not form a r-jjecipitate in this case at all. This fail- 

 ure is attributed to the reaction of ferric chloride vrith the resinous 

 acids in the wood. It was apparent that a considerable sjnount of the resins 

 had steeled from the 7/ood, in that an appreciable quantity of a p-umiay mater- 

 ial remained as a residue v;hen the solution was concentrated subsequently. 

 This occurrence is to be expected, since the temperature used is above the 

 softenj.ng Doint of the resins. It is suggested, as explanation for the 

 interfei-ence in the oxide formation, that much of the ferric chloride 

 reacted ^^ith the resin in a manner such as is sho^m by the following equa- 

 tion, which is, admittedly, an over-simplif ication: ferric chloride + 

 resinous acids — -> ferric resinated + hydrpcloric acid. The formation of 

 ferric resinate .-ould decrease the ferric ion concentration markedly inas- 

 much as it is fairly insoluble aid the compound remaining in solution would 

 be largelj'- undissociated, Thourh there is no evidence that the ,0-form 

 was actually obtained in the :ood, the treatment had some definite effect 

 on the constitution of the ;ood and for this reason the blocks were placed 

 in the sea to determine their performance. It is possible that some modi- 

 fications in t'^is method may be found so as to obtain suitable results. 

 It is a further possibility that some types of wood other than the southern 

 yellow pine used in these experiiiients might not contain such prohibitive 

 amounts of interfering substances. 



