A novel structural descriptor, called molecular electronegativity- distance vector (MEDV), is developed to describe the structure of an organic compound consisting of carbon, hydrogen, oxygen, nitrogen, sulphur and so on. Using tryptophan as an example, which contains element C, H, N and O and a five-membered and a six-membered ring and diverse chemical bonds, a procedure for calculating MEDV of the molecule is illustrated and a computer program written in True BASIC language is devised. the novel MEDV descriptor can be used alone to study the quantitative structure-property relationship (QSPR) of many properties such as boiling point, critical temperature, retention index, and so on for some types of organic compounds including alkanes, alcohols and polycyclic aromatic hydrocarbons.

Key words: ALKANE, ALCOHOL, POLYNUCLEAR ATOMATIC HYDROCARBON P