It crystallizes in needles (from hot water), which melt at 146.5° C. and boil at 269°-270° C. It is readily soluble in hot water, alcohol and dilute hydrochloric acid. Nitrous acid converts it into nitrosoindazole; whilst on heating with the alkyl iodides it is converted into alkyl indazoles.
A series of compounds isomeric with these alkyl derivatives is known, and can be considered as derived from the ring system
These isomers are called isindazoles, and may be prepared by the reduction of the nitroso-ortho-alkylamino-acetophenones with zinc dust and water or acetic acid. The indazoles are weak bases, which crystallize readily. Phenyl indazole, on reduction with sodium and absolute alcohol, gives a dihydro derivative (K. L. Paal, Ber., 1891, 24, p. 963).
For other derivatives, see E. Fischer and J. Tafel, Ann. 1885, 227, p. 314.
INDEMNITY (through Fr. indemnité, Lat. indemnis, free from damage or loss; in-, negative, and damnum, loss), in law, an undertaking, either express or implied, to compensate another for loss or damage, or for trouble or expense incurred; also the sum so paid (see [Contract]; and [Insurance]: Marine). An act of indemnity is a statute passed for the purpose either of relieving persons from disabilities and penalties to which they have rendered themselves liable or to make legal transactions which, when they took place, were illegal. An act or bill of indemnity used to be passed every session by the English parliament for the relief of those who had unwittingly neglected to qualify themselves in certain respects for the holding of offices, &c., as, for example, justices, without taking the necessary oaths. The Promissory Oaths Act 1868 rendered this unnecessary.
INDENE, C9H8, a hydrocarbon found in the fraction of the coal tar distillate boiling between 176° and 182° C., and from which it may be extracted by means of its picrate (G. Kramer, A. Spilker, Ber., 1890, 23, p. 3276). It may also be obtained by distilling the calcium salt of hydrindene carboxylic acid, C6H4(CH2)2·CH·COOH. It is an oil which boils at 179.5°-180.5°, and has a specific gravity 1.04 (15° C.). Dilute nitric acid oxidizes it to phthalic acid, and sodium reduces it in alcoholic solution to hydrindene, C9H10. A. v. Baeyer and W. H. Perkin (Ber., 1884, 17, p. 125) by the action of sodiomalonic ester on ortho-xylylene bromide obtained a hydrindene dicarboxylic ester,