What is the difference between 互相 hu4xiang1 hùxiānɡ and 相互xiang1hu4 xiānɡhù

As for the 相互hùxiānɡ and 互相 xiānɡhù 。

When they are used as the adv., they are same.

For example, you could say 我们互相帮助 wǒmen hùxiānɡ bānɡzhù，我们相互帮助wǒmen xiānɡhù bānɡzhù。

But I think people use 互相hùxiānɡ more often than 相互(xiānghù) in this case.

相互xiānɡhù could be used as adj. too, but 互相 hùxiānɡ could't.

 You could say 中国和新加坡相互的关系很好 zhōnɡɡuó hé xīnjiāpō xiānɡhù de ɡuānxìn hěnhǎo。

but you shouldn't see 中国和新加坡互相的关系很好 zhōnɡɡuó hé xīnjiāpō hùxiānɡ de ɡuānxì hěnhǎo 。