Government debentures generally come as long term or short term debentures. The security term generally consists of twelve months to five years, but these can be sold in the secondary market. There is also tax relief on the income from government debentures and because of this, they are always in demand. Debentures are always different from stocks and bonds, but basically, all three are different forms of investment.
The difference is the varying risk factors and returns reflected by the higher risks and corresponding higher returns of the debentures.
When buying a stock, he/she becomes one of the owners of the company and faces "floating" fortunes, related to the company's financial graph. Debentures are a more secured investment as payments with high interest rates are guaranteed.
The government is bound to pay interest on the borrowed money and once the debenture matures, the borrowed money is returned. It is actually the interest which is gained from government debentures.
Government debentures and government bonds are similar, but bonds carry more security than debentures. In both of these investments, interest and value is guaranteed, but in case of liquidation, bond holders receive the payment first.
Debenture holders have no collateral which they can claim from a company in case of bankruptcy. To compensate such losses, high interest rates are paid. Bondholders have the collateral and are more secure.