A special class of conjugated hydrocarbons is known as phenylenes, which is composed of a special arrangement of six- and four-membered rings. In particular, any two six-membered rings (hexagons) are not adjacent, and every four-membered ring (square) is adjacent to a pair of nonadjacent hexagons. If each hexagon of phenylene is adjacent only to two squares, then the obtained chain is called the phenylene chain. The main object of this paper is to determine the expected values of the sum-connectivity, harmonic, symmetric division, variable inverse sum degree and general Randic indices for this class of conjugated hydrocarbons. The comparisons between the expected values of these indices with respect to the random phenylene chains have been determined explicitly. The graphical illustrations have been given in terms of the differences between the expected values of these indices.

一类特殊的共轭碳氢化合物称为亚苯基，由六元和四元环的特殊排列组成。特别地，任何两个六元环（六边形）不相邻，并且每个四元环（正方形）与一对不相邻的六边形相邻。如果亚苯基的每个六边形仅与两个正方形相邻，则所获得的链称为亚苯基链。本文的主要目的是确定此类共轭碳氢化合物的总连接度，谐波，对称除法，可变逆总和度和一般兰迪指数的期望值。这些指数相对于无规亚苯基链的预期值之间的比较已明确确定。