Indium Hydr oxides

Indium has only one stable oxidation state (-+-3) within the electrochemical window of water, but it forms several relatively stable compounds with oxygen 

Properties Specific surface area 81 mVg, TEM image available [1679]. 

Properties Crystalline, XRD results, TGA and DTA results, SEM and TEM image available, specific surface area 56 in7g [1679]. 

A solution 0.0002-0.008 M in In and 0.0003-0.01 M in HNO, (in the presence or absence of sulfate, sulfateiln ratio 1.25) was heated at 100°C for 2 h, then rapidly quenched to room temperature and washed. 

Properties SEM images available (also for different sulfate In ratios) [116]. 

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They also isolated the new metal by simple chemical methods. The zinc blende sample was dissolved in add and several metals, Pb, Cu, As and Sn, were removed by predpitation with hydr< en sulfide. The filtrate was oxidized and neutralized with ammonia in great excess. Zinc stayed dissolved whQe a predpitate of iron hydroxide, also containing indium, was obtained The hydroxide predpitate was dissolved in add, and iron (and some indium) was predpitated again by carefiil addition of sodium carbonate. From the filtrate indium hydroxide was predpitated by sodium carbonate in excess. They prepared indium by reduction of the oxide with charcoal in front of the narrow end of a blowpipe. The new metal was, according to the discoverers, a soft dudUe metal, with which one could mark a paper, and it was of lighter color than lead, similar to tin . 

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