center
tag aligns the buttons within it as expected:
<ion-footer>
<ion-toolbar>
<center>
<button royal>
Contacts
<ion-icon name="contact"></ion-icon>
</button>
<button secondary>
Receive
<ion-icon name="arrow-round-back"></ion-icon>
</button>
<button danger>
Wallet
<ion-icon name="home"></ion-icon>
</button>
<button secondary>
Send
<ion-icon name="send"></ion-icon>
</button>
<button danger>
Transactions
<ion-icon name="archive"></ion-icon>
</button>
<button danger>
About
<ion-icon name="information-circle"></ion-icon>
</button>
</center>
</ion-toolbar>
</ion-footer>