direction:rtl demo

<style>

body {font:14px/18px Consolas;}

div {

  width:100px;padding:10px;

  margin:10px 0px 30px 0px;

  border:1px solid #CCC;

}

.float {overflow:hidden;} /*加overflow防止容器坍缩*/

.float span {float:right;}

.align {text-align:right;}

.align span {text-align:left;}

.direction {direction:rtl;}

.direction span {direction:ltr;display:inline-block;}

</style>

float right

<div class="float">

  <span>次</span><span>碳</span><span>酸</span><span>钴</span>

</div>

align right

<div class="align">

  <span>次</span><span>碳</span><span>酸</span><span>钴</span>

</div>

direction rtl

<div class="direction">

  <span>次</span><span>碳</span><span>酸</span><span>钴</span>

</div>